2.0.14 pkg version

Generate and publish documentation to GitHub Pages

.github/workflows/build-docs.yml

@@ -0,0 +1,31 @@
+name: build-docs
+
+on:
+  push:
+    branches:
+      - master
+      - feature/docs
+
+jobs:
+  run-docfx:
+    if: "!(contains(github.event.head_commit.message, '[skip ci]') || contains(github.event.head_commit.message, '[ci skip]'))"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2
+        with:
+          repository: Cysharp/DocfxTemplate
+          path: docs/_DocfxTemplate
+      - uses: Kirbyrawr/docfx-action@master
+        name: Docfx metadata
+        with:
+          args: metadata docs/docfx.json
+      - uses: Kirbyrawr/docfx-action@master
+        name: Docfx build
+        with:
+          args: build docs/docfx.json
+      - name: Publish to GitHub Pages
+        uses: peaceiris/actions-gh-pages@v3
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: docs/_site

.github/workflows/build-release.yml

@@ -20,18 +20,17 @@ jobs:
       # set release tag(*.*.*) to env.GIT_TAG
       - run: echo ::set-env name=GIT_TAG::${GITHUB_REF#refs/tags/}
 
-      # build CommandTools first (use dotnet run command in ZLogger.csproj)
-      - run: dotnet build -c Release ./tools/CommandTools/CommandTools.csproj
+      # build and pack
       - run: dotnet build -c Release -p:Version=${{ env.GIT_TAG }}
       - run: dotnet test -c Release --no-build
-      - run: dotnet pack ./src/ZLogger/ZLogger.csproj -c Release --no-build -p:Version=${{ env.GIT_TAG }}
+      - run: dotnet pack ./src/UniTask.NetCore/UniTask.NetCore.csproj -c Release --no-build -p:Version=${{ env.GIT_TAG }}
 
       # Store artifacts.
       - uses: actions/upload-artifact@v1
         with:
           name: nuget
-          path: ./src/ZLogger/bin/Release/ZLogger.${{ env.GIT_TAG }}.nupkg
-      
+          path: ./src/UniTask.NetCore/bin/Release/UniTask.${{ env.GIT_TAG }}.nupkg
+
   build-unity:
     strategy:
       matrix:
@@ -57,15 +56,13 @@ jobs:
       # Execute scripts: Export Package
       - name: Export unitypackage
         run: /opt/Unity/Editor/Unity -quit -batchmode -nographics -silent-crashes -logFile -projectPath . -executeMethod PackageExporter.Export
-        working-directory: src/ZLogger.Unity
-        env:
-          UNITY_PACKAGE_VERSION: ${{ env.GIT_TAG }}
+        working-directory: src/UniTask
 
-      # Store artifacts.
-      - uses: actions/upload-artifact@v1
+      # Store artifacts.      
+      - uses: actions/upload-artifact@v2
         with:
-          name: ZLogger.Unity.${{ env.GIT_TAG }}.unitypackage
-          path: ./src/ZLogger.Unity/ZLogger.Unity.${{ env.GIT_TAG }}.unitypackage
+          name: UniTask.${{ env.GIT_TAG }}.unitypackage
+          path: ./src/UniTask/UniTask.${{ env.GIT_TAG }}.unitypackage
 
   create-release:
     needs: [build-dotnet, build-unity]
@@ -91,7 +88,7 @@ jobs:
         tag_name: ${{ github.ref }}
         release_name: Ver.${{ github.ref }}
 
-    # Download (All) Artifacts to current directory
+    # Download(All) Artifacts to current directory
     - uses: actions/download-artifact@v2-preview
 
     # Upload to NuGet
@@ -103,6 +100,6 @@ jobs:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       with:
         upload_url: ${{ steps.create_release.outputs.upload_url }}
-        asset_path: ./ZLogger.Unity.${{ env.GIT_TAG }}.unitypackage/ZLogger.Unity.${{ env.GIT_TAG }}.unitypackage
-        asset_name: ZLogger.Unity.${{ env.GIT_TAG }}.unitypackage
+        asset_path: ./UniTask.${{ env.GIT_TAG }}.unitypackage/UniTask.${{ env.GIT_TAG }}.unitypackage
+        asset_name: UniTask.${{ env.GIT_TAG }}.unitypackage
         asset_content_type: application/octet-stream

.gitignore

@@ -157,3 +157,51 @@ src/UniTask/UniTask.Tests.csproj
 src/UniTask/UniTask.Tests.Editor.csproj
 
 src/UniTask/UniTask.*.unitypackage
+
+src/UniTask/UniTask.Linq.csproj
+
+src/UniTask/DOTween.Modules.csproj
+
+src/UniTask/Unity.Addressables.csproj
+
+src/UniTask/Unity.Addressables.Editor.csproj
+
+src/UniTask/Unity.Analytics.DataPrivacy.csproj
+
+src/UniTask/Unity.Recorder.csproj
+
+src/UniTask/Unity.Recorder.Editor.csproj
+
+src/UniTask/Unity.ResourceManager.csproj
+
+src/UniTask/Unity.Rider.Editor.csproj
+
+src/UniTask/Unity.ScriptableBuildPipeline.csproj
+
+src/UniTask/Unity.ScriptableBuildPipeline.Editor.csproj
+
+src/UniTask/Unity.TextMeshPro.csproj
+
+src/UniTask/Unity.TextMeshPro.Editor.csproj
+
+src/UniTask/Unity.Timeline.csproj
+
+src/UniTask/Unity.Timeline.Editor.csproj
+
+src/UniTask/Unity.VisualStudio.Editor.csproj
+
+src/UniTask/Unity.VSCode.Editor.csproj
+
+src/UniTask/UnityEditor.CacheServer.csproj
+
+src/UniTask/UnityEditor.TestRunner.csproj
+
+src/UniTask/UnityEditor.UI.csproj
+
+src/UniTask/UnityEngine.Advertisements.csproj
+
+src/UniTask/UnityEngine.Monetization.csproj
+
+src/UniTask/UnityEngine.TestRunner.csproj
+
+src/UniTask/UnityEngine.UI.csproj

README.md

@@ -2,46 +2,63 @@ UniTask
 ===
 [![GitHub Actions](https://github.com/Cysharp/UniTask/workflows/Build-Debug/badge.svg)](https://github.com/Cysharp/UniTask/actions) [![Releases](https://img.shields.io/github/release/Cysharp/UniTask.svg)](https://github.com/Cysharp/UniTask/releases)
 
-Provides an efficient async/await integration to Unity.
+Provides an efficient async/await integration to Unity. 
+
+* Struct based `UniTask<T>` and custom AsyncMethodBuilder to achive zero allocation
+* All Unity AsyncOperations and Coroutine to awaitable
+* PlayerLoop based task(`UniTask.Yield`, `UniTask.Delay`, `UniTask.DelayFrame`, etc..) that enable to replace all coroutine operation
+* MonoBehaviour Message Events and uGUI Events as awaitable/async-enumerable
+* Completely run on Unity's PlayerLoop so don't use thread and run on WebGL, wasm, etc.
+* Asynchronous LINQ, with Channel and AsyncReactiveProperty
+* TaskTracker window to prevent memory leak
+* Highly compatible behaviour with Task/ValueTask/IValueTaskSource
 
 <!-- START doctoc generated TOC please keep comment here to allow auto update -->
 <!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
 ## Table of Contents
 
 - [Getting started](#getting-started)
-- [`UniTask<T>`](#unitaskt)
+- [Basics of UniTask and AsyncOperation](#basics-of-unitask-and-asyncoperation)
 - [Cancellation and Exception handling](#cancellation-and-exception-handling)
 - [Progress](#progress)
+- [PlayerLoop](#playerloop)
+- [async void vs async UniTaskVoid](#async-void-vs-async-unitaskvoid)
 - [UniTaskTracker](#unitasktracker)
-- [Reusable Promises](#reusable-promises)
-- [awaitable Events](#awaitable-events)
-- [async void vs async UniTask/UniTaskVoid](#async-void-vs-async-unitaskunitaskvoid)
+- [External Assets](#external-assets)
+- [AsyncEnumerable and Async LINQ](#asyncenumerable-and-async-linq)
+- [Awaitable Events](#awaitable-events)
+- [Channel](#channel)
 - [For Unit Testing](#for-unit-testing)
-- [Method List](#method-list)
+- [Pooling Configuration](#pooling-configuration)
+- [API References](#api-references)
 - [UPM Package](#upm-package)
-- [ECS, PlayerLoop](#ecs-playerloop)
+  - [Install via git URL](#install-via-git-url)
+  - [Install via OpenUPM](#install-via-openupm)
+- [.NET Core](#net-core)
 - [License](#license)
 
 <!-- END doctoc generated TOC please keep comment here to allow auto update -->
 
-
 Getting started
 ---
-Install package(`UniRx.Async.unitypackage`) is available in [UniTask/releases](https://github.com/Cysharp/UniTask/releases) page.
+Install via [UPM package](#upm-package) or asset package(`UniTask.*.*.*.unitypackage`) available in [UniTask/releases](https://github.com/Cysharp/UniTask/releases) page.
 
 ```csharp
 // extension awaiter/methods can be used by this namespace
-using UniRx.Async;
+using Cysharp.Threading.Tasks;
 
 // You can return type as struct UniTask<T>(or UniTask), it is unity specialized lightweight alternative of Task<T>
-// no(or less) allocation and fast excution for zero overhead async/await integrate with Unity
+// zero allocation and fast excution for zero overhead async/await integrate with Unity
 async UniTask<string> DemoAsync()
 {
     // You can await Unity's AsyncObject
     var asset = await Resources.LoadAsync<TextAsset>("foo");
     
-    // .ConfigureAwait accepts progress callback
-    await SceneManager.LoadSceneAsync("scene2").ConfigureAwait(Progress.Create<float>(x => Debug.Log(x)));
+    // .WithCancellation enables Cancel, GetCancellationTokenOnDestroy synchornizes with lifetime of GameObject
+    var asset2 = await Resources.LoadAsync<TextAsset>("foo").WithCancellation(this.GetCancellationTokenOnDestroy());
+
+    // .ToUniTask accepts progress callback(and all options), Progress.Create is a lightweight alternative of IProgress<T>
+    await SceneManager.LoadSceneAsync("scene2").ToUniTask(Progress.Create<float>(x => Debug.Log(x)));
     
     // await frame-based operation like coroutine
     await UniTask.DelayFrame(100); 
@@ -50,11 +67,14 @@ async UniTask<string> DemoAsync()
     await UniTask.Delay(TimeSpan.FromSeconds(10), ignoreTimeScale: false);
     
     // replacement of WaitForEndOfFrame(or other timing like yield return null, yield return WaitForFixedUpdate)
-    await UniTask.Yield(PlayerLoopTiming.PostLateUpdate);
+    await UniTask.Yield(PlayerLoopTiming.LastPostLateUpdate);
     
     // replacement of yield return WaitUntil
     await UniTask.WaitUntil(() => isActive == false);
 
+    // special helper of WaitUntil
+    await UniTask.WaitUntilValueChanged(this, x => x.isActive);
+
     // You can await IEnumerator coroutine
     await FooCoroutineEnumerator();
 
@@ -77,6 +97,9 @@ async UniTask<string> DemoAsync()
 
     // concurrent async-wait and get result easily by tuple syntax
     var (google, bing, yahoo) = await UniTask.WhenAll(task1, task2, task3);
+
+    // shorthand of WhenAll, tuple can await directly
+    var (google2, bing2, yahoo2) = await (task1, task2, task3);
     
     // You can handle timeout easily
     await GetTextAsync(UnityWebRequest.Get("http://unity.com")).Timeout(TimeSpan.FromMilliseconds(300));
@@ -86,47 +109,36 @@ async UniTask<string> DemoAsync()
 }
 ```
 
-`UniTask<T>`
+Basics of UniTask and AsyncOperation
 ---
-UniTask feature rely on C# 7.0([task-like custom async method builder feature](https://github.com/dotnet/roslyn/blob/master/docs/features/task-types.md)) so required  Unity version is after `Unity 2018.3`.
+UniTask feature rely on C# 7.0([task-like custom async method builder feature](https://github.com/dotnet/roslyn/blob/master/docs/features/task-types.md)) so required Unity version is after `Unity 2018.3`, officialy lower support version is `Unity 2018.4.13f1`.
 
-Why UniTask(custom task-like object) is required? Because Task is too heavy, not matched to Unity threading(single-thread). UniTask does not use thread and SynchronizationContext because almost Unity's asynchronous object is automaticaly dispatched by Unity's engine layer. It acquires more fast and more less allocation, completely integrated with Unity.
+Why UniTask(custom task-like object) is required? Because Task is too heavy, not matched to Unity threading(single-thread). UniTask does not use thread and SynchronizationContext/ExecutionContext because almost Unity's asynchronous object is automaticaly dispatched by Unity's engine layer. It acquires more fast and more less allocation, completely integrated with Unity.
 
-> More details, please see this slide: [Deep Dive async/await in Unity with UniTask(EN)
-](https://www.slideshare.net/neuecc/deep-dive-asyncawait-in-unity-with-unitasken)
+You can await `AsyncOperation`, `ResourceRequest`, `AssetBundleRequest`, `AssetBundleCreateRequest`, `UnityWebRequestAsyncOperation`, `IEnumerator` and others when `using Cysharp.Threading.Tasks;`.
 
-You can await `AsyncOperation`, `ResourceRequest`, `UnityWebRequestAsyncOperation`, `IEnumerator` and others when using `UniRx.Async`.
-
-`UniTask.Delay`, `UniTask.Yield`, `UniTask.Timeout` that is frame-based timer operators(no uses thread so works on WebGL publish) driven by custom PlayerLoop(Unity 2018 experimental feature). In default, UniTask initialize automatically when application begin, but it is override all. If you want to append PlayerLoop, please call `PlayerLoopHelper.Initialize(ref yourCustomizedPlayerLoop)` manually.
-
-> Before Unity 2019.3, Unity does not have `PlayerLooop.GetCurrentPlayerLoop` so you can't use with Unity ECS package in default. If you want to use with ECS and before Unity 2019.3, you can use this hack below.
+UniTask provides three pattern of extension methods.
 
 ```csharp
-// Get ECS Loop.
-var playerLoop = ScriptBehaviourUpdateOrder.CurrentPlayerLoop;
-
-// Setup UniTask's PlayerLoop.
-PlayerLoopHelper.Initialize(ref playerLoop);
+* await asyncOperation;
+* .WithCancellation(CancellationToken);
+* .ToUniTask(IProgress, PlayerLoopTiming, CancellationToken);
 ```
 
-`UniTask.WhenAll`, `UniTask.WhenAny` is like Task.WhenAll/WhenAny but return type is more useful.
+`WithCancellation` is a simple version of `ToUniTask`, both returns `UniTask`. Details of cancellation, see: [Cancellation and Exception handling](#cancellation-and-exception-handling) section.
 
-`UniTask.ctor(Func<UniTask>)` is like the embeded [`AsyncLazy<T>`](https://blogs.msdn.microsoft.com/pfxteam/2011/01/15/asynclazyt/)
+The type of `UniTask` can use utility like `UniTask.WhenAll`, `UniTask.WhenAny`. It is like Task.WhenAll/WhenAny but return type is more useful, returns value tuple so can deconsrtuct each result and pass multiple type.
 
 ```csharp
 public class SceneAssets
 {
-    public readonly UniTask<Sprite> Front;
-    public readonly UniTask<Sprite> Background;
-    public readonly UniTask<Sprite> Effect;
-
     public SceneAssets()
     {
-        // ctor(Func) overload is AsyncLazy, initialized once when await.
-        // and after it, await returns zero-allocation value immediately.
-        Front = new UniTask<Sprite>(() => LoadAsSprite("foo"));
-        Background = new UniTask<Sprite>(() => LoadAsSprite("bar"));
-        Effect = new UniTask<Sprite>(() => LoadAsSprite("baz"));
+        // parallel load.
+        var (a, b, c) = await UniTask.WhenAll(
+            LoadAsSprite("foo"),
+            LoadAsSprite("bar"),
+            LoadAsSprite("baz"));
     }
 
     async UniTask<Sprite> LoadAsSprite(string path)
@@ -152,13 +164,32 @@ public UniTask<int> WrapByUniTaskCompletionSource()
 }
 ```
 
-You can convert Task -> UniTask: `AsUniTask`, `UniTask` -> `UniTask<AsyncUnit>`: `AsAsyncUnitUniTask`(this is useful to use WhenAll/WhenAny), `UniTask<T>` -> `UniTask`: `AsUniTask`.
+You can convert Task -> UniTask: `AsUniTask`, `UniTask` -> `UniTask<AsyncUnit>`: `AsAsyncUnitUniTask`, `UniTask<T>` -> `UniTask`: `AsUniTask`. `UniTask<T>` -> `UniTask`'s conversion cost is free.
 
-If you want to convert async to coroutine, you can use `UniTask.ToCoroutine`, this is useful to use only allow coroutine system.
+If you want to convert async to coroutine, you can use `.ToCoroutine()`, this is useful to use only allow coroutine system.
+
+UniTask can not await twice. This is a similar constraint to the [ValueTask/IValueTaskSource](https://docs.microsoft.com/en-us/dotnet/api/system.threading.tasks.valuetask-1?view=netcore-3.1) introduced in .NET Standard 2.1.
+
+> The following operations should never be performed on a ValueTask<TResult> instance:
+>
+> * Awaiting the instance multiple times.
+> * Calling AsTask multiple times.
+> * Using .Result or .GetAwaiter().GetResult() when the operation hasn't yet completed, or using them multiple times.
+> * Using more than one of these techniques to consume the instance.
+>
+> If you do any of the above, the results are undefined.
+
+```csharp
+var task = UniTask.DelayFrame(10);
+await task;
+await task; // NG, throws Exception
+```
+
+Store to the class field, you can use `UniTask.Lazy` that gurantee call multipletimes. `.Prevent()` allows for multiple calls (internally cached results). This is useful when multiple calls in a function scope.
 
 Cancellation and Exception handling
 ---
-Some UniTask factory methods have `CancellationToken cancellation = default(CancellationToken)` parameter. Andalso some async operation for unity have `ConfigureAwait(..., CancellationToken cancellation = default(CancellationToken))` extension methods. 
+Some UniTask factory methods have `CancellationToken cancellationToken = default` parameter. Andalso some async operation for unity have `WithCancellation(CancellationToken)` and `ToUniTask(..., CancellationToken cancellation = default)` extension methods. 
 
 You can pass `CancellationToken` to parameter by standard [`CancellationTokenSource`](https://docs.microsoft.com/en-us/dotnet/api/system.threading.cancellationtokensource).
 
@@ -170,7 +201,7 @@ cancelButton.onClick.AddListener(() =>
     cts.Cancel();
 });
 
-await UnityWebRequest.Get("http://google.co.jp").SendWebRequest().ConfigureAwait(cancellation: cts.Token);
+await UnityWebRequest.Get("http://google.co.jp").SendWebRequest().WithCancellation(cts.Token);
 
 await UniTask.DelayFrame(1000, cancellationToken: cts.Token);
 ```
@@ -184,7 +215,7 @@ await UniTask.DelayFrame(1000, cancellationToken: this.GetCancellationTokenOnDes
 
 When detect cancellation, all methods throws `OperationCanceledException` and propagate to upstream. `OperationCanceledException` is special exception, if not handled this exception, finally it is propagated to `UniTaskScheduler.UnobservedTaskException`.
 
-Default behaviour of received unhandled exception is write log as warning. Log level can change by `UniTaskScheduler.UnobservedExceptionWriteLogType`. If you want to change custom beavhiour, set action to `UniTaskScheduler.UnobservedTaskException.`
+Default behaviour of received unhandled exception is write log as exception. Log level can change by `UniTaskScheduler.UnobservedExceptionWriteLogType`. If you want to change custom beavhiour, set action to `UniTaskScheduler.UnobservedTaskException.`
 
 If you want to cancel behaviour in async UniTask method, throws `OperationCanceledException` manually.
 
@@ -223,23 +254,23 @@ if (isCanceled)
 }
 ```
 
-Note: Only suppress throws if you call it directly into the most source method.
+Note: Only suppress throws if you call it directly into the most source method. Otherwise, the return value will be converted, but the entire pipeline will not be suppressed throws.
 
 Progress
 ---
-Some async operation for unity have `ConfigureAwait(IProgress<float> progress = null, ...)` extension methods. 
+Some async operation for unity have `ToUniTask(IProgress<float> progress = null, ...)` extension methods. 
 
 ```csharp
 var progress = Progress.Create<float>(x => Debug.Log(x));
 
 var request = await UnityWebRequest.Get("http://google.co.jp")
     .SendWebRequest()
-    .ConfigureAwait(progress: progress);
+    .ToUniTask(progress: progress);
 ```
 
-Should not use `new System.Progress<T>`, because it allocate every times. Use `UniRx.Async.Progress` instead. Progress factory has two methods, `Create` and `CreateOnlyValueChanged`. `CreateOnlyValueChanged` calls only when progress value changed. Should not use `new System.Progress<T>`, it allocate every times.
+You should not use standard `new System.Progress<T>`, because it causes allocation every times. Use `Cysharp.Threading.Tasks.Progress` instead. This progress factory has two methods, `Create` and `CreateOnlyValueChanged`. `CreateOnlyValueChanged` calls only when progress value changed.
 
-Implements interface is more better.
+Implements IProgress interface to caller is more better, there is no allocation of lambda.
 
 ```csharp
 public class Foo : MonoBehaviour, IProgress<float>
@@ -253,16 +284,129 @@ public class Foo : MonoBehaviour, IProgress<float>
     {
         var request = await UnityWebRequest.Get("http://google.co.jp")
             .SendWebRequest()
-            .ConfigureAwait(progress: this); // pass this
+            .ToUniTask(progress: this); // pass this
     }
 }
 ```
 
+PlayerLoop
+---
+UniTask is run on custom [PlayerLoop](https://docs.unity3d.com/ScriptReference/LowLevel.PlayerLoop.html). UniTask's playerloop based method(such as `Delay`, `DelayFrame`, `asyncOperation.ToUniTask`, etc...) accepts this `PlayerLoopTiming`.
+
+```csharp
+public enum PlayerLoopTiming
+{
+    Initialization = 0,
+    LastInitialization = 1,
+
+    EarlyUpdate = 2,
+    LastEarlyUpdate = 3,
+
+    FixedUpdate = 4,
+    LastFixedUpdate = 5,
+
+    PreUpdate = 6,
+    LastPreUpdate = 7,
+
+    Update = 8,
+    LastUpdate = 9,
+
+    PreLateUpdate = 10,
+    LastPreLateUpdate = 11,
+
+    PostLateUpdate = 12,
+    LastPostLateUpdate = 13
+}
+```
+
+It indicates when to run, you can check [PlayerLoopList.md](https://gist.github.com/neuecc/bc3a1cfd4d74501ad057e49efcd7bdae) to Unity's default playerloop and injected UniTask's custom loop.
+
+`PlayerLoopTiming.Update` is similar as `yield return null` in coroutine, but it is called before Update(Update is called on `ScriptRunBehaviourUpdate`, yield return null is called on `ScriptRunDelayedDynamicFrameRate`). If change timing to `PlayerLoopTiming.LastUpdate`, called after these Unity's update methods.
+
+`PlayerLoopTiming.FixedUpdate` is similar as `WaitForFixedUpdate`, `PlayerLoopTiming.LastPostLateUpdate` is similar as `WaitForEndOfFrame` in coroutine.
+
+In stacktrace, you can check where is running in playerloop.
+
+![image](https://user-images.githubusercontent.com/46207/83735571-83caea80-a68b-11ea-8d22-5e22864f0d24.png)
+
+In default, UniTask's PlayerLoop is initialized at `[RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]`.
+
+The order in which methods are called in BeforeSceneLoad is indeterminate, so if you want to use UniTask in other BeforeSceneLoad methods, you should try to initialize it before this.
+
+```csharp
+// AfterAssembliesLoaded is called before BeforeSceneLoad
+[RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.AfterAssembliesLoaded)]
+public static void InitUniTaskLoop()
+{
+    var loop = PlayerLoop.GetCurrentPlayerLoop();
+    Cysharp.Threading.Tasks.PlayerLoopHelper.Initialize(ref loop);
+}
+```
+
+If you import Unity's `Entities` package, that reset custom player loop to default at `BeforeSceneLoad` and inject ECS's loop. When Unity call ECS's inject method after UniTask's initialize method, UniTask will no longer work.
+
+To solve this issue, you can re-initialize UniTask PlayerLoop after ECS initialized.
+
+```csharp
+// Get ECS Loop.
+var playerLoop = ScriptBehaviourUpdateOrder.CurrentPlayerLoop;
+
+// Setup UniTask's PlayerLoop.
+PlayerLoopHelper.Initialize(ref playerLoop);
+```
+
+async void vs async UniTaskVoid
+---
+`async void` is a standard C# taks system so does not run on UniTask systems. It is better not to use. `async UniTaskVoid` is a lightweight version of `async UniTask` because it does not have awaitable completion and report error immediately to `UniTaskScheduler.UnobservedTaskException`. If you don't require to await it(fire and forget), use `UniTaskVoid` is better. Unfortunately to dismiss warning, require to using with `Forget()`.
+
+```csharp
+public async UniTaskVoid FireAndForgetMethod()
+{
+    // do anything...
+    await UniTask.Yield();
+}
+
+public void Caller()
+{
+    FireAndForgetMethod().Forget();
+}
+```
+
+Also UniTask have `Forget` method, it is similar with UniTaskVoid and same effects with it. However still UniTaskVoid is more efficient if completely do not use await。
+
+```csharp
+public async UniTask DoAsync()
+{
+    // do anything...
+    await UniTask.Yield();
+}
+
+public void Caller()
+{
+    DoAsync().Forget();
+}
+```
+
+Using async lambda in register event, it is used `async void`. To avoid it, you can use `UniTask.Action` or `UniTask.UnityAction` that creates delegate via `async UniTaskVoid` lambda.
+
+```csharp
+Action actEvent;
+UnityAction unityEvent; // especially used in uGUI
+
+// Bad: async void
+actEvent += async () => { };
+unityEvent += async () => { };
+
+// Ok: create Action delegate by lambda
+actEvent += UniTask.Action(async () => { await UniTask.Yield(); });
+unityEvent += UniTask.UnityAction(async () => { await UniTask.Yield(); });
+```
+
 UniTaskTracker
 ---
 useful for check(leak) UniTasks. You can open tracker window in `Window -> UniTask Tracker`.
 
-![](https://user-images.githubusercontent.com/46207/50421527-abf1cf80-0883-11e9-928a-ffcd47b8c454.png)
+![image](https://user-images.githubusercontent.com/46207/83527073-4434bf00-a522-11ea-86e9-3b3975b26266.png)
 
 * Enable AutoReload(Toggle) - Reload automatically.
 * Reload - Reload view.
@@ -272,38 +416,89 @@ useful for check(leak) UniTasks. You can open tracker window in `Window -> UniTa
 
 For debug use, enable tracking and capture stacktrace is useful but it it decline performance. Recommended usage is enable both to find task leak, and when done, finally disable both.
 
-Reusable Promises
+External Assets
 ---
-Some UniTask factory can reuse to reduce allocation. The list is `Yield`, `Delay`, `DelayFrame`, `WaitUntil`, `WaitWhile`, `WaitUntilValueChanged`.
+In default, UniTask supports DOTween and Addressables(`AsyncOperationHandle` and `AsyncOpereationHandle<T>` as awaitable).
+
+For DOTween support, require to `com.demigiant.dotween` import from [OpenUPM](https://openupm.com/packages/com.demigiant.dotween/) or define `UNITASK_DOTWEEN_SUPPORT` to enable it.
 
 ```csharp
-var reusePromise = UniTask.DelayFrame(10);
+// sequential
+await transform.DOMoveX(2, 10);
+await transform.DOMoveZ(5, 20);
 
-for (int i = 0; i < 10; i++)
+// parallel with cancellation
+var ct = this.GetCancellationTokenOnDestroy();
+
+await UniTask.WhenAll(
+    transform.DOMoveX(10, 3).WithCancellation(ct),
+    transform.DOScale(10, 3).WithCancellation(ct));
+```
+
+AsyncEnumerable and Async LINQ
+---
+Unity 2020.2.0a12 supports C# 8.0 so you can use `await foreach`. This is the new Update notation in async era.
+
+```csharp
+// Unity 2020.2.0a12, C# 8.0
+await foreach (var _ in UniTaskAsyncEnumerable.EveryUpdate(token))
 {
-    await reusePromise;
+    Debug.Log("Update() " + Time.frameCount);
 }
 ```
 
-awaitable Events
----
-Unity events can await like `OnClickAsync`, `OnCollisionEnterAsync`. It can use by `UniRx.Async.Triggers`.
+In a C# 7.3 environment, you can use the `ForEachAsync` method to work in almost the same way.
 
 ```csharp
-using UniRx.Async.Triggers;
-
-async UniTask TripleClick(CancellationToken token)
+// C# 7.3(Unity 2018.3~)
+await UniTaskAsyncEnumerable.EveryUpdate(token).ForEachAsync(_ =>
 {
-    await button.OnClickAsync(token);
-    await button.OnClickAsync(token);
-    await button.OnClickAsync(token);
+    Debug.Log("Update() " + Time.frameCount);
+});
+```
+
+UniTaskAsyncEnumerable implements asynchronous LINQ, similar to LINQ in `IEnumerable<T>` or Rx in `IObservable<T>`. All standard LINQ query operators can be applied to asynchronous streams. For example, the following code shows how to apply a Where filter to a button-click asynchronous stream that runs once every two clicks.
+
+```csharp
+await okButton.OnClickAsAsyncEnumerable().Where((x, i) => i % 2 == 0).ForEachAsync(_ =>
+{
+});
+```
+
+Async LINQ is enabled when `using Cysharp.Threading.Tasks.Linq;`, and `UniTaskAsyncEnumerable` is defined in `UniTask.Linq` asmdef.
+
+It's closer to UniRx (Reactive Extensions), but UniTaskAsyncEnumerable is a pull-based asynchronous stream, whereas Rx was a push-based asynchronous stream. Note that although similar, the characteristics are different and the details behave differently along with them.
+
+`UniTaskAsyncEnumerable` is the entry point like `Enumerbale`. In addition to the standard query operators, there are other generators for Unity such as `EveryUpdate`, `Timer`, `TimerFrame`, `Interval`, `IntervalFrame`, and `EveryValueChanged`. And also added additional UniTask original query operators like `Append`, `Prepend`, `DistinctUntilChanged`, `ToHashSet`, `Buffer`, `CombineLatest`, `Do`, `Never`, `ForEachAsync`, `Pairwise`, `Publish`, `Queue`, `Return`, `SkipUntilCanceled`, `TakeUntilCanceled`, `TakeLast`.
+
+The method with Func as an argument has three additional overloads, `***Await`, `***AwaitWithCancellation`.
+
+```csharp
+Select(Func<T, TR> selector)
+SelectAwait(Func<T, UniTask<TR>> selector)
+SelectAwaitWithCancellation(Func<T, CancellationToken, UniTask<TR>> selector)
+```
+
+If you want to use the `async` method inside the func, use the `***Await` or `***AwaitWithCancellation`.
+
+Awaitable Events
+---
+All uGUI component implements `***AsAsyncEnumerable` to convert asynchronous streams of events.
+
+```csharp
+async UniTask TripleClick()
+{
+    // In default, used button.GetCancellationTokenOnDestroy to manage lieftime of async
+    await button.OnClickAsync();
+    await button.OnClickAsync();
+    await button.OnClickAsync();
     Debug.Log("Three times clicked");
 }
 
 // more efficient way
-async UniTask TripleClick(CancellationToken token)
+async UniTask TripleClick()
 {
-    using (var handler = button.GetAsyncClickEventHandler(token))
+    using (var handler = button.GetAsyncClickEventHandler())
     {
         await handler.OnClickAsync();
         await handler.OnClickAsync();
@@ -311,11 +506,126 @@ async UniTask TripleClick(CancellationToken token)
         Debug.Log("Three times clicked");
     }
 }
+
+// use async LINQ
+async UniTask TripleClick(CancellationToken token)
+{
+    await button.OnClickAsAsyncEnumerable().Take(3).Last();
+    Debug.Log("Three times clicked");
+}
+
+// use async LINQ2
+async UniTask TripleClick(CancellationToken token)
+{
+    await button.OnClickAsAsyncEnumerable().Take(3).ForEachAsync(_ =>
+    {
+        Debug.Log("Every clicked");
+    });
+    Debug.Log("Three times clicked, complete.");
+}
 ```
 
-async void vs async UniTask/UniTaskVoid
+All MonoBehaviour message events can convert async-streams by `AsyncTriggers` that can enable by `using Cysharp.Threading.Tasks.Triggers;`.
+
+```csharp
+using Cysharp.Threading.Tasks.Triggers;
+
+async UniTaskVoid MonitorCollision()
+{
+    await gameObject.OnCollisionEnterAsync();
+    Debug.Log("Collision Enter");
+    /* do anything */
+
+    await gameObject.OnCollisionExitAsync();
+    Debug.Log("Collision Exit");
+}
+```
+
+Similar as uGUI event, AsyncTrigger can get by `GetAsync***Trigger` and trigger it self is UniTaskAsyncEnumerable.
+
+```csharp
+// use await multiple times, get AsyncTriggerHandler is more efficient.
+using(var trigger = this.GetOnCollisionEnterAsyncHandler())
+{
+    await OnCollisionEnterAsync();
+    await OnCollisionEnterAsync();
+    await OnCollisionEnterAsync();
+}
+
+// every moves.
+await this.GetAsyncMoveTrigger().ForEachAsync(axisEventData =>
+{
+});
+```
+
+`AsyncReactiveProperty`, `AsyncReadOnlyReactiveProperty` is UniTask version of UniTask's ReactiveProperty.
+
+`BindTo` extension method of `IUniTaskAsyncEnumerable<T>` for binding asynchronous stream values to Unity components(Text/Selectable/TMP/Text).
+
+A pull-type asynchronous stream does not get the next values until the asynchronous processing in the sequence is complete. This could spill data from push-type events such as buttons.
+
+```csharp
+// can not get click event during 3 seconds complete.
+await button.OnClickAsAsyncEnumerable().ForEachAwaitAsync()
+{
+    await UniTask.Delay(TimeSpan.FromSeconds(3));
+}
+```
+
+It is useful(prevent double-click) but not useful in sometimes.
+
+Using `Queue()` method, which will also queue events during asynchronous processing.
+
+```csharp
+// queued message in asynchronous processing
+await button.OnClickAsAsyncEnumerable().Queue().ForEachAwaitAsync()
+{
+    await UniTask.Delay(TimeSpan.FromSeconds(3));
+}
+```
+
+Channel
 ---
-`async void` is standard C# system so does not run on UniTask systems. It is better not to use. `async UniTaskVoid` is lightweight version of `async UniTask` because it does not have awaitable completion. If you don't require to await it(fire and forget), use `UniTaskVoid` is better. Unfortunately to dismiss warning, require to using with `Forget()`.
+`Channel` is same as [System.Threading.Tasks.Channels](https://docs.microsoft.com/ja-jp/dotnet/api/system.threading.channels?view=netcore-3.1) that is similar as GoLang Channel.
+
+Currently only supports multiple-producer, single-consumer unbounded channel. It can create by `Channel.CreateSingleConsumerUnbounded<T>()`.
+
+For producer(`.Writer`), `TryWrite` to push value and `TryComplete` to complete channel. For consumer(`.Reader`), `TryRead`, `WaitToReadAsync`, `ReadAsync`, `Completion` and `ReadAllAsync` to read queued messages.
+
+`ReadAllAsync` returns `IUniTaskAsyncEnumerable<T>` so query LINQ operators. Reader only allows single-consumer but use `.Publish()` query operator to enable multicast message. For example, make pub/sub utility.
+
+```csharp
+public class AsyncMessageBroker<T> : IDisposable
+{
+    Channel<T> channel;
+
+    IConnectableUniTaskAsyncEnumerable<T> multicastSource;
+    IDisposable connection;
+
+    public AsyncMessageBroker()
+    {
+        channel = Channel.CreateSingleConsumerUnbounded<T>();
+        multicastSource = channel.Reader.ReadAllAsync().Publish();
+        connection = multicastSource.Connect(); // Publish returns IConnectableUniTaskAsyncEnumerable.
+    }
+
+    public void Publish(T value)
+    {
+        channel.Writer.TryWrite(value);
+    }
+
+    public IUniTaskAsyncEnumerable<T> Subscribe()
+    {
+        return multicastSource;
+    }
+
+    public void Dispose()
+    {
+        channel.Writer.TryComplete();
+        connection.Dispose();
+    }
+}
+```
 
 For Unit Testing
 ---
@@ -342,46 +652,82 @@ public IEnumerator DelayIgnore() => UniTask.ToCoroutine(async () =>
 });
 ```
 
-Method List
+UniTask itself's unit test is written by Unity Test Runner and [Cysharp/RuntimeUnitTestToolkit](https://github.com/Cysharp/RuntimeUnitTestToolkit) to check on CI and IL2CPP working.
+
+Pooling Configuration
 ---
+UniTask is aggressively caching async promise object to achive zero allocation. In default, cache all promises but you can configure `TaskPool.SetMaxPoolSize` to your value, the value indicates cache size per type. `TaskPool.GetCacheSizeInfo` returns current cached object in pool.
+
 ```csharp
-UniTask.WaitUntil
-UniTask.WaitWhile
-UniTask.WaitUntilValueChanged
-UniTask.SwitchToThreadPool
-UniTask.SwitchToTaskPool
-UniTask.SwitchToMainThread
-UniTask.SwitchToSynchronizationContext
-UniTask.Yield
-UniTask.Run
-UniTask.Lazy
-UniTask.Void
-UniTask.ConfigureAwait
-UniTask.DelayFrame
-UniTask.Delay(..., bool ignoreTimeScale = false, ...) parameter
+foreach (var (type, size) in TaskPool.GetCacheSizeInfo())
+{
+    Debug.Log(type + ":" + size);
+}
 ```
 
+API References
+---
+UniTask's API References is hosted at [cysharp.github.io/UniTask](https://cysharp.github.io/UniTask/api/Cysharp.Threading.Tasks.html) by [DocFX](https://dotnet.github.io/docfx/) and [Cysharp/DocfXTemplate](https://github.com/Cysharp/DocfxTemplate).
+
+For example, UniTask's factory methods can see at [UniTask#methods](https://cysharp.github.io/UniTask/api/Cysharp.Threading.Tasks.UniTask.html#methods-1). UniTaskAsyncEnumerable's factory/extension methods can see at [UniTaskAsyncEnumerable#methods](https://cysharp.github.io/UniTask/api/Cysharp.Threading.Tasks.Linq.UniTaskAsyncEnumerable.html#methods-1).
+
 UPM Package
 ---
-After Unity 2019.3.4f1, Unity 2020.1a21, that support path query parameter of git package. You can add `https://github.com/Cysharp/UniTask.git?path=Assets/UniRx.Async` to Package Manager
+### Install via git URL
+
+After Unity 2019.3.4f1, Unity 2020.1a21, that support path query parameter of git package. You can add `https://github.com/Cysharp/UniTask.git?path=src/UniTask/Assets/Plugins/UniTask` to Package Manager
 
 ![image](https://user-images.githubusercontent.com/46207/79450714-3aadd100-8020-11ea-8aae-b8d87fc4d7be.png)
 
-![image](https://user-images.githubusercontent.com/46207/79450774-56b17280-8020-11ea-91eb-21e1f51eb60c.png)
+![image](https://user-images.githubusercontent.com/46207/83702872-e0f17c80-a648-11ea-8183-7469dcd4f810.png)
 
-or add `"com.cysharp.unitask": "https://github.com/Cysharp/UniTask.git?path=Assets/UniRx.Async"` to `Packages/manifest.json`.
+or add `"com.cysharp.unitask": "https://github.com/Cysharp/UniTask.git?path=src/UniTask/Assets/Plugins/UniTask"` to `Packages/manifest.json`.
 
-If you want to set a target version, UniTask is using `*.*.*` release tag so you can specify a version like `#1.3.0`. For example `https://github.com/Cysharp/UniTask.git?path=Assets/UniRx.Async#1.3.1`.
+If you want to set a target version, UniTask is using `*.*.*` release tag so you can specify a version like `#2.0.13`. For example `https://github.com/Cysharp/UniTask.git?path=src/UniTask/Assets/Plugins/UniTask#2.0.13`.
 
-ECS, PlayerLoop
+### Install via OpenUPM
+
+The package is available on the [openupm registry](https://openupm.com). It's recommended to install it via [openupm-cli](https://github.com/openupm/openupm-cli).
+
+```
+openupm add com.cysharp.unitask
+```
+
+.NET Core
 ---
-TODO:
+For .NET Core, use NuGet.
+
+> PM> Install-Package [UniTask](https://www.nuget.org/packages/UniTask)
+
+UniTask of .NET Core version is a subset of Unity UniTask, removed PlayerLoop dependent methods.
+
+It runs at higher performance than the standard Task/ValueTask, but you should be careful to ignore the ExecutionContext/SynchronizationContext when using it. `AysncLocal` also does not work because it ignores ExecutionContext.
+
+If you use UniTask internally, but provide ValueTask as an external API, you can write like the following(Inspired by [PooledAwait](https://github.com/mgravell/PooledAwait)).
 
 ```csharp
-var loop = PlayerLoop.GetCurrentPlayerLoop();
-PlayerLoopHelper.Initialize(ref loop);
+public class ZeroAllocAsyncAwaitInDotNetCore
+{
+    public ValueTask<int> DoAsync(int x, int y)
+    {
+        return Core(this, x, y);
+
+        static async UniTask<int> Core(ZeroAllocAsyncAwaitInDotNetCore self, int x, int y)
+        {
+            // do anything...
+            await Task.Delay(TimeSpan.FromSeconds(x + y));
+            await UniTask.Yield();
+
+            return 10;
+        }
+    }
+}
 ```
 
+.NET Core version is intended to allow users to use UniTask as an interface when sharing code with Unity (such as [Cysharp/MagicOnion](https://github.com/Cysharp/MagicOnion/)). .NET Core version of UniTask enables smooth code sharing.
+
+Utility methods such as WhenAll which is equivalent to UniTask are provided as [Cysharp/ValueTaskSupplement](https://github.com/Cysharp/ValueTaskSupplement).
+
 License
 ---
-This library is under the MIT License.
+This library is under the MIT License.

docs/.gitignore

@@ -0,0 +1,10 @@
+###############
+#    folder   #
+###############
+/**/DROP/
+/**/TEMP/
+/**/packages/
+/**/bin/
+/**/obj/
+_site
+_DocfxTemplate

docs/api/.gitignore

@@ -0,0 +1,5 @@
+###############
+#  temp file  #
+###############
+*.yml
+.manifest

docs/docfx.json

@@ -0,0 +1,70 @@
+{
+  "metadata": [
+    {
+      "src": [
+        {
+          "files": [
+            "UniTask/Assets/Plugins/UniTask/Runtime/**/*.cs"
+          ],
+          "src": "../src"
+        }
+      ],
+      "dest": "api",
+      "disableGitFeatures": false,
+      "disableDefaultFilter": false
+    }
+  ],
+  "build": {
+    "globalMetadata": {
+      "_disableContribution": true,
+      "_appTitle": "UniTask"
+    },
+    "content": [
+      {
+        "files": [
+          "api/**.yml",
+          "api/index.md"
+        ]
+      },
+      {
+        "files": [
+          "articles/**.md",
+          "articles/**/toc.yml",
+          "toc.yml",
+          "*.md"
+        ]
+      }
+    ],
+    "resource": [
+      {
+        "files": [
+          "images/**"
+        ]
+      }
+    ],
+    "overwrite": [
+      {
+        "files": [
+          "apidoc/**.md"
+        ],
+        "exclude": [
+          "obj/**",
+          "_site/**"
+        ]
+      }
+    ],
+    "dest": "_site",
+
+    "globalMetadataFiles": [],
+    "fileMetadataFiles": [],
+    "template": [
+      "_DocfxTemplate/templates/default-v2.5.2",
+      "_DocfxTemplate/templates/cysharp"
+    ],
+    "postProcessors": [],
+    "markdownEngineName": "markdig",
+    "noLangKeyword": false,
+    "keepFileLink": false,
+    "cleanupCacheHistory": false
+  }
+}

docs/index.md

@@ -0,0 +1,8 @@
+---
+title: Home
+---
+# UniTask
+
+Provides an efficient async/await integration to Unity.
+
+https://github.com/Cysharp/UniTask

docs/toc.yml

@@ -0,0 +1,11 @@
+- name: API Documentation
+  href: api/
+  homepage: api/Cysharp.Threading.Tasks.html
+
+- name: Repository
+  href: https://github.com/Cysharp/UniTask
+  homepage: https://github.com/Cysharp/UniTask
+
+- name: Releases
+  href: https://github.com/Cysharp/UniTask/releases
+  homepage: https://github.com/Cysharp/UniTask/releases

src/UniTask.NetCore/NetCore/UniTask.AsValueTask.cs

@@ -1,7 +1,6 @@
 #pragma warning disable 0649
 
 using System;
-using System.Runtime.CompilerServices;
 using System.Threading.Tasks;
 using System.Threading.Tasks.Sources;
 
@@ -9,115 +8,91 @@ namespace Cysharp.Threading.Tasks
 {
     public static class UniTaskValueTaskExtensions
     {
-        public static ValueTask AsValueTask(this UniTask task)
+        public static ValueTask AsValueTask(this in UniTask task)
         {
-            ref var core = ref Unsafe.As<UniTask, UniTaskToValueTask>(ref task);
-            if (core.source == null)
-            {
-                return default;
-            }
-            
-            return new ValueTask(new UniTaskValueTaskSource(core.source), core.token);
+#if NETSTANDARD2_0
+            return new ValueTask(new UniTaskValueTaskSource(task), 0);
+#else
+            return task;
+#endif
         }
 
-        public static ValueTask<T> AsValueTask<T>(this UniTask<T> task)
+        public static ValueTask<T> AsValueTask<T>(this in UniTask<T> task)
         {
-            ref var core = ref Unsafe.As<UniTask<T>, UniTaskToValueTask<T>>(ref task);
-            if (core.source == null)
-            {
-                return new ValueTask<T>(core.result);
-            }
-
-            return new ValueTask<T>(new UniTaskValueTaskSource<T>(core.source), core.token);
+#if NETSTANDARD2_0
+            return new ValueTask<T>(new UniTaskValueTaskSource<T>(task), 0);
+#else
+            return task;
+#endif
         }
 
-        struct UniTaskToValueTask
+        public static UniTask<T> AsUniTask<T>(this ValueTask<T> task, bool useCurrentSynchronizationContext = true)
         {
-            public IUniTaskSource source;
-            public short token;
+            // NOTE: get _obj and _token directly for low overhead conversion but not yet implemented.
+            return task.AsTask().AsUniTask(useCurrentSynchronizationContext);
         }
 
+        public static UniTask AsUniTask(this ValueTask task, bool useCurrentSynchronizationContext = true)
+        {
+            return task.AsTask().AsUniTask(useCurrentSynchronizationContext);
+        }
+
+#if NETSTANDARD2_0
+
         class UniTaskValueTaskSource : IValueTaskSource
         {
-            readonly IUniTaskSource source;
+            readonly UniTask task;
+            readonly UniTask.Awaiter awaiter;
 
-            public UniTaskValueTaskSource(IUniTaskSource source)
+            public UniTaskValueTaskSource(UniTask task)
             {
-                this.source = source;
+                this.task = task;
+                this.awaiter = task.GetAwaiter();
             }
 
             public void GetResult(short token)
             {
-                source.GetResult(token);
+                awaiter.GetResult();
             }
 
             public ValueTaskSourceStatus GetStatus(short token)
             {
-                var status = source.GetStatus(token);
-                switch (status)
-                {
-                    case UniTaskStatus.Pending:
-                        return ValueTaskSourceStatus.Pending;
-                    case UniTaskStatus.Succeeded:
-                        return ValueTaskSourceStatus.Succeeded;
-                    case UniTaskStatus.Faulted:
-                        return ValueTaskSourceStatus.Faulted;
-                    case UniTaskStatus.Canceled:
-                        return ValueTaskSourceStatus.Canceled;
-                    default:
-                        return (ValueTaskSourceStatus)status;
-                }
+                return (ValueTaskSourceStatus)task.Status;
             }
 
             public void OnCompleted(Action<object> continuation, object state, short token, ValueTaskSourceOnCompletedFlags flags)
             {
-                source.OnCompleted(continuation, state, token);
+                awaiter.SourceOnCompleted(continuation, state);
             }
         }
 
-        struct UniTaskToValueTask<T>
-        {
-            public IUniTaskSource<T> source;
-            public T result;
-            public short token;
-        }
-
         class UniTaskValueTaskSource<T> : IValueTaskSource<T>
         {
-            readonly IUniTaskSource<T> source;
+            readonly UniTask<T> task;
+            readonly UniTask<T>.Awaiter awaiter;
 
-            public UniTaskValueTaskSource(IUniTaskSource<T> source)
+            public UniTaskValueTaskSource(UniTask<T> task)
             {
-                this.source = source;
+                this.task = task;
+                this.awaiter = task.GetAwaiter();
             }
 
             public T GetResult(short token)
             {
-                return source.GetResult(token);
+                return awaiter.GetResult();
             }
 
             public ValueTaskSourceStatus GetStatus(short token)
             {
-                var status = source.GetStatus(token);
-                switch (status)
-                {
-                    case UniTaskStatus.Pending:
-                        return ValueTaskSourceStatus.Pending;
-                    case UniTaskStatus.Succeeded:
-                        return ValueTaskSourceStatus.Succeeded;
-                    case UniTaskStatus.Faulted:
-                        return ValueTaskSourceStatus.Faulted;
-                    case UniTaskStatus.Canceled:
-                        return ValueTaskSourceStatus.Canceled;
-                    default:
-                        return (ValueTaskSourceStatus)status;
-                }
+                return (ValueTaskSourceStatus)task.Status;
             }
 
             public void OnCompleted(Action<object> continuation, object state, short token, ValueTaskSourceOnCompletedFlags flags)
             {
-                source.OnCompleted(continuation, state, token);
+                awaiter.SourceOnCompleted(continuation, state);
             }
         }
+
+#endif
     }
 }

src/UniTask.NetCore/NetCore/UniTask.Delay.cs

@@ -0,0 +1,39 @@
+//using Cysharp.Threading.Tasks.Internal;
+//using System;
+//using System.Collections.Concurrent;
+//using System.Runtime.CompilerServices;
+//using System.Threading;
+
+//namespace Cysharp.Threading.Tasks
+//{
+//    public partial struct UniTask
+//    {
+//        public static UniTask Delay()
+//        {
+//            return default;
+//        }
+
+//        sealed class DelayPromise : IUniTaskSource
+//        {
+//            public void GetResult(short token)
+//            {
+//                throw new NotImplementedException();
+//            }
+
+//            public UniTaskStatus GetStatus(short token)
+//            {
+//                throw new NotImplementedException();
+//            }
+
+//            public void OnCompleted(Action<object> continuation, object state, short token)
+//            {
+//                throw new NotImplementedException();
+//            }
+
+//            public UniTaskStatus UnsafeGetStatus()
+//            {
+//                throw new NotImplementedException();
+//            }
+//        }
+//    }
+//}

src/UniTask.NetCore/NetCore/UniTask.Yield.cs

@@ -1,4 +1,6 @@
-using System;
+using Cysharp.Threading.Tasks.Internal;
+using System;
+using System.Collections.Concurrent;
 using System.Runtime.CompilerServices;
 using System.Threading;
 
@@ -41,7 +43,11 @@ namespace Cysharp.Threading.Tasks
                     }
                     else
                     {
+#if NETCOREAPP3_1
+                        ThreadPool.UnsafeQueueUserWorkItem(ThreadPoolWorkItem.Create(continuation), false);
+#else
                         ThreadPool.UnsafeQueueUserWorkItem(WaitCallbackDelegate, continuation);
+#endif
                     }
                 }
 
@@ -50,6 +56,47 @@ namespace Cysharp.Threading.Tasks
                     ((Action)state).Invoke();
                 }
             }
+
+#if NETCOREAPP3_1
+
+            sealed class ThreadPoolWorkItem : IThreadPoolWorkItem, ITaskPoolNode<ThreadPoolWorkItem>
+            {
+                static TaskPool<ThreadPoolWorkItem> pool;
+                public ThreadPoolWorkItem NextNode { get; set; }
+
+                static ThreadPoolWorkItem()
+                {
+                    TaskPool.RegisterSizeGetter(typeof(ThreadPoolWorkItem), () => pool.Size);
+                }
+
+                Action continuation;
+
+                [MethodImpl(MethodImplOptions.AggressiveInlining)]
+                public static ThreadPoolWorkItem Create(Action continuation)
+                {
+                    if (!pool.TryPop(out var item))
+                    {
+                        item = new ThreadPoolWorkItem();
+                    }
+
+                    item.continuation = continuation;
+                    return item;
+                }
+
+                [MethodImpl(MethodImplOptions.AggressiveInlining)]
+                public void Execute()
+                {
+                    var call = continuation;
+                    continuation = null;
+                    if (call != null)
+                    {
+                        pool.TryPush(this);
+                        call.Invoke();
+                    }
+                }
+            }
+
+#endif
         }
     }
 }

src/UniTask.NetCore/UniTask.NetCore.csproj

@@ -1,11 +1,30 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>netstandard2.0</TargetFramework>
+        <TargetFrameworks>netcoreapp3.1;netstandard2.1;netstandard2.0</TargetFrameworks>
         <AssemblyName>UniTask</AssemblyName>
+        <LangVersion>8.0</LangVersion>
         <RootNamespace>Cysharp.Threading.Tasks</RootNamespace>
+
+        <!-- NuGet Packaging -->
+        <Id>UniTask</Id>
+        <PackageVersion>$(Version)</PackageVersion>
+        <Company>Cysharp</Company>
+        <Authors>Cysharp</Authors>
+        <Copyright>© Cysharp, Inc.</Copyright>
+        <PackageTags>task;async</PackageTags>
+        <Description>Provides an efficient async/await integration to Unity and .NET Core.</Description>
+        <PackageProjectUrl>https://github.com/Cysharp/UniTask</PackageProjectUrl>
+        <RepositoryUrl>$(PackageProjectUrl)</RepositoryUrl>
+        <RepositoryType>git</RepositoryType>
+        <PackageLicenseExpression>MIT</PackageLicenseExpression>
+        <PackageIcon>Icon.png</PackageIcon>
     </PropertyGroup>
 
+    <ItemGroup>
+        <None Include="Icon.png" Pack="true" PackagePath="/" />
+    </ItemGroup>
+
     <ItemGroup>
         <Compile Include="..\UniTask\Assets\Plugins\UniTask\Runtime\**\*.cs"
                  Exclude="

src/UniTask.NetCoreSandbox/AllocationCheck.cs

@@ -0,0 +1,258 @@
+using BenchmarkDotNet.Attributes;
+using System.Linq;
+using BenchmarkDotNet.Configs;
+using BenchmarkDotNet.Diagnosers;
+using BenchmarkDotNet.Exporters;
+using BenchmarkDotNet.Jobs;
+using BenchmarkDotNet.Running;
+using Cysharp.Threading.Tasks;
+using PooledAwait;
+using System;
+using System.Runtime.ExceptionServices;
+using System.Threading.Tasks;
+using System.Threading;
+using System.Runtime.CompilerServices;
+using Cysharp.Threading.Tasks.CompilerServices;
+using System.Collections.Concurrent;
+
+[Config(typeof(BenchmarkConfig))]
+public class AllocationCheck
+{
+    // note: all the benchmarks use Task/Task<T> for the public API, because BenchmarkDotNet
+    // doesn't work reliably with more exotic task-types (even just ValueTask fails); instead,
+    // we'll obscure the cost of the outer awaitable by doing a relatively large number of
+    // iterations, so that we're only really measuring the inner loop
+    private const int InnerOps = 1000;
+
+    [Benchmark(OperationsPerInvoke = InnerOps)]
+    public async Task ViaUniTask()
+    {
+        for (int i = 0; i < InnerOps; i++)
+        {
+            var a = Core();
+            var b = Core();
+            var c = Core();
+            await a;
+            await b;
+            await c;
+        }
+
+        static async UniTask Core()
+        {
+            await new TestAwaiter(false, UniTaskStatus.Succeeded);
+            await new TestAwaiter(false, UniTaskStatus.Succeeded);
+            await new TestAwaiter(false, UniTaskStatus.Succeeded);
+        }
+    }
+
+    [Benchmark(OperationsPerInvoke = InnerOps)]
+    public async Task<int> ViaUniTaskT()
+    {
+        var sum = 0;
+        for (int i = 0; i < InnerOps; i++)
+        {
+            var a = Core();
+            var b = Core();
+            var c = Core();
+            sum += await a;
+            sum += await b;
+            sum += await c;
+        }
+        return sum;
+
+        static async UniTask<int> Core()
+        {
+            var a = await new TestAwaiter<int>(false, UniTaskStatus.Succeeded, 10);
+            var b = await new TestAwaiter<int>(false, UniTaskStatus.Succeeded, 10);
+            var c = await new TestAwaiter<int>(false, UniTaskStatus.Succeeded, 10);
+            return 10;
+        }
+    }
+
+    //[Benchmark(OperationsPerInvoke = InnerOps)]
+    //[Benchmark]
+    public void ViaUniTaskVoid()
+    {
+        for (int i = 0; i < InnerOps; i++)
+        {
+            Core().Forget();
+            Core().Forget();
+            Core().Forget();
+        }
+
+        static async UniTaskVoid Core()
+        {
+            await new TestAwaiter(false, UniTaskStatus.Succeeded);
+            await new TestAwaiter(false, UniTaskStatus.Succeeded);
+            await new TestAwaiter(false, UniTaskStatus.Succeeded);
+        }
+    }
+
+    struct Foo : IAsyncStateMachine
+    {
+        public AsyncUniTaskVoidMethodBuilder builder;
+        public TestAwaiter awaiter;
+        public TestAwaiter awaiterawaiter;
+
+        public int state;
+
+        public void MoveNext()
+        {
+            switch (state)
+            {
+                case -1:
+                    awaiterawaiter = awaiter.GetAwaiter();
+                    if (awaiterawaiter.IsCompleted)
+                    {
+                        goto case 0;
+                    }
+                    else
+                    {
+                        state = 0;
+                        builder.AwaitUnsafeOnCompleted(ref awaiterawaiter, ref this);
+                        return;
+                    }
+
+                case 0:
+                default:
+                    goto END;
+            }
+
+            END:
+            builder.SetResult();
+        }
+
+        public void SetStateMachine(IAsyncStateMachine stateMachine)
+        {
+
+        }
+    }
+}
+
+public class TaskTestException : Exception
+{
+
+}
+
+public struct TestAwaiter : ICriticalNotifyCompletion
+{
+    readonly UniTaskStatus status;
+    readonly bool isCompleted;
+
+    public TestAwaiter(bool isCompleted, UniTaskStatus status)
+    {
+        this.isCompleted = isCompleted;
+        this.status = status;
+    }
+
+    public TestAwaiter GetAwaiter() => this;
+
+    public bool IsCompleted => isCompleted;
+
+    public void GetResult()
+    {
+        switch (status)
+        {
+            case UniTaskStatus.Faulted:
+                throw new TaskTestException();
+            case UniTaskStatus.Canceled:
+                throw new OperationCanceledException();
+            case UniTaskStatus.Pending:
+            case UniTaskStatus.Succeeded:
+            default:
+                break;
+        }
+    }
+
+    public void OnCompleted(Action continuation)
+    {
+        ThreadPool.UnsafeQueueUserWorkItem(ThreadPoolWorkItem.Create(continuation), false);
+    }
+
+    public void UnsafeOnCompleted(Action continuation)
+    {
+        ThreadPool.UnsafeQueueUserWorkItem(ThreadPoolWorkItem.Create(continuation), false);
+    }
+
+
+}
+
+public struct TestAwaiter<T> : ICriticalNotifyCompletion
+{
+    readonly UniTaskStatus status;
+    readonly bool isCompleted;
+    readonly T value;
+
+    public TestAwaiter(bool isCompleted, UniTaskStatus status, T value)
+    {
+        this.isCompleted = isCompleted;
+        this.status = status;
+        this.value = value;
+    }
+
+    public TestAwaiter<T> GetAwaiter() => this;
+
+    public bool IsCompleted => isCompleted;
+
+    public T GetResult()
+    {
+        switch (status)
+        {
+            case UniTaskStatus.Faulted:
+                throw new TaskTestException();
+            case UniTaskStatus.Canceled:
+                throw new OperationCanceledException();
+            case UniTaskStatus.Pending:
+            case UniTaskStatus.Succeeded:
+            default:
+                return value;
+        }
+    }
+
+    public void OnCompleted(Action continuation)
+    {
+        ThreadPool.UnsafeQueueUserWorkItem(ThreadPoolWorkItem.Create(continuation), false);
+    }
+
+    public void UnsafeOnCompleted(Action continuation)
+    {
+        ThreadPool.UnsafeQueueUserWorkItem(ThreadPoolWorkItem.Create(continuation), false);
+    }
+}
+
+public sealed class ThreadPoolWorkItem : IThreadPoolWorkItem
+{
+    public static readonly ConcurrentQueue<ThreadPoolWorkItem> pool = new ConcurrentQueue<ThreadPoolWorkItem>();
+
+    public static void CreatePoolItems(int count)
+    {
+        for (int i = 0; i < count; i++)
+        {
+            pool.Enqueue(new ThreadPoolWorkItem());
+        }
+    }
+
+    Action continuation;
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static ThreadPoolWorkItem Create(Action continuation)
+    {
+        if (!pool.TryDequeue(out var item))
+        {
+            item = new ThreadPoolWorkItem();
+        }
+
+        item.continuation = continuation;
+        return item;
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public void Execute()
+    {
+        var call = continuation;
+        continuation = null;
+        pool.Enqueue(this);
+
+        call.Invoke();
+    }
+}

src/UniTask.NetCoreSandbox/Benchmark.cs

@@ -0,0 +1,283 @@
+using BenchmarkDotNet.Attributes;
+using System.Linq;
+using BenchmarkDotNet.Configs;
+using BenchmarkDotNet.Diagnosers;
+using BenchmarkDotNet.Exporters;
+using BenchmarkDotNet.Jobs;
+using BenchmarkDotNet.Running;
+using Cysharp.Threading.Tasks;
+using PooledAwait;
+using System;
+using System.Runtime.ExceptionServices;
+using System.Threading.Tasks;
+using System.Threading;
+using System.Runtime.CompilerServices;
+using Cysharp.Threading.Tasks.CompilerServices;
+
+//class Program
+//{
+//    static void Main(string[] args)
+//    {
+//        var switcher = new BenchmarkSwitcher(new[]
+//        {
+//            typeof(StandardBenchmark)
+//        });
+
+//#if DEBUG
+//        var b = new StandardBenchmark();
+
+//#else
+//        switcher.Run(args);
+//#endif
+//    }
+//}
+
+public class BenchmarkConfig : ManualConfig
+{
+    public BenchmarkConfig()
+    {
+        AddDiagnoser(MemoryDiagnoser.Default);
+        AddJob(Job.ShortRun.WithLaunchCount(1).WithIterationCount(1).WithWarmupCount(1)/*.RunOncePerIteration()*/);
+    }
+}
+
+// borrowed from PooledAwait
+
+[Config(typeof(BenchmarkConfig))]
+[GroupBenchmarksBy(BenchmarkLogicalGroupRule.ByCategory)]
+[CategoriesColumn]
+public class ComparisonBenchmarks
+{
+    // note: all the benchmarks use Task/Task<T> for the public API, because BenchmarkDotNet
+    // doesn't work reliably with more exotic task-types (even just ValueTask fails); instead,
+    // we'll obscure the cost of the outer awaitable by doing a relatively large number of
+    // iterations, so that we're only really measuring the inner loop
+    private const int InnerOps = 1000;
+
+    public bool ConfigureAwait { get; set; } = false;
+
+    [Benchmark(OperationsPerInvoke = InnerOps, Description = ".NET")]
+    [BenchmarkCategory("Task<T>")]
+    public async Task<int> ViaTaskT()
+    {
+        int sum = 0;
+        for (int i = 0; i < InnerOps; i++)
+            sum += await Inner(1, 2).ConfigureAwait(ConfigureAwait);
+        return sum;
+
+        static async Task<int> Inner(int x, int y)
+        {
+            int i = x;
+            await Task.Yield();
+            i *= y;
+            await Task.Yield();
+            return 5 * i;
+        }
+    }
+
+    [Benchmark(OperationsPerInvoke = InnerOps, Description = ".NET")]
+    [BenchmarkCategory("Task")]
+    public async Task ViaTask()
+    {
+        for (int i = 0; i < InnerOps; i++)
+            await Inner().ConfigureAwait(ConfigureAwait);
+
+        static async Task Inner()
+        {
+            await Task.Yield();
+            await Task.Yield();
+        }
+    }
+
+    [Benchmark(OperationsPerInvoke = InnerOps, Description = ".NET")]
+    [BenchmarkCategory("ValueTask<T>")]
+    public async Task<int> ViaValueTaskT()
+    {
+        int sum = 0;
+        for (int i = 0; i < InnerOps; i++)
+            sum += await Inner(1, 2).ConfigureAwait(ConfigureAwait);
+        return sum;
+
+        static async ValueTask<int> Inner(int x, int y)
+        {
+            int i = x;
+            await Task.Yield();
+            i *= y;
+            await Task.Yield();
+            return 5 * i;
+        }
+    }
+
+    [Benchmark(OperationsPerInvoke = InnerOps, Description = ".NET")]
+    [BenchmarkCategory("ValueTask")]
+    public async Task ViaValueTask()
+    {
+        for (int i = 0; i < InnerOps; i++)
+            await Inner().ConfigureAwait(ConfigureAwait);
+
+        static async ValueTask Inner()
+        {
+            await Task.Yield();
+            await Task.Yield();
+        }
+    }
+
+    [Benchmark(OperationsPerInvoke = InnerOps, Description = "Pooled")]
+    [BenchmarkCategory("ValueTask<T>")]
+    public async Task<int> ViaPooledValueTaskT()
+    {
+        int sum = 0;
+        for (int i = 0; i < InnerOps; i++)
+            sum += await Inner(1, 2).ConfigureAwait(ConfigureAwait);
+        return sum;
+
+        static async PooledValueTask<int> Inner(int x, int y)
+        {
+            int i = x;
+            await Task.Yield();
+            i *= y;
+            await Task.Yield();
+            return 5 * i;
+        }
+    }
+
+    [Benchmark(OperationsPerInvoke = InnerOps, Description = "Pooled")]
+    [BenchmarkCategory("ValueTask")]
+    public async Task ViaPooledValueTask()
+    {
+        for (int i = 0; i < InnerOps; i++)
+            await Inner().ConfigureAwait(ConfigureAwait);
+
+        static async PooledValueTask Inner()
+        {
+            await Task.Yield();
+            await Task.Yield();
+        }
+    }
+
+    [Benchmark(OperationsPerInvoke = InnerOps, Description = "Pooled")]
+    [BenchmarkCategory("Task<T>")]
+    public async Task<int> ViaPooledTaskT()
+    {
+        int sum = 0;
+        for (int i = 0; i < InnerOps; i++)
+            sum += await Inner(1, 2).ConfigureAwait(ConfigureAwait);
+        return sum;
+
+        static async PooledTask<int> Inner(int x, int y)
+        {
+            int i = x;
+            await Task.Yield();
+            i *= y;
+            await Task.Yield();
+            return 5 * i;
+        }
+    }
+
+    [Benchmark(OperationsPerInvoke = InnerOps, Description = "Pooled")]
+    [BenchmarkCategory("Task")]
+    public async Task ViaPooledTask()
+    {
+        for (int i = 0; i < InnerOps; i++)
+            await Inner().ConfigureAwait(ConfigureAwait);
+
+        static async PooledTask Inner()
+        {
+            await Task.Yield();
+            await Task.Yield();
+        }
+    }
+
+    // ---
+
+    //[Benchmark(OperationsPerInvoke = InnerOps, Description = "UniTaskVoid")]
+    //[BenchmarkCategory("UniTask")]
+    //public async Task ViaUniTaskVoid()
+    //{
+    //    for (int i = 0; i < InnerOps; i++)
+    //    {
+    //        await Inner();
+    //    }
+
+    //    static async UniTaskVoid Inner()
+    //    {
+    //        await UniTask.Yield();
+    //        await UniTask.Yield();
+    //    }
+    //}
+
+    [Benchmark(OperationsPerInvoke = InnerOps, Description = "UniTask")]
+    [BenchmarkCategory("UniTask")]
+    public async Task ViaUniTask()
+    {
+        for (int i = 0; i < InnerOps; i++)
+        {
+            await Inner();
+        }
+
+        static async UniTask Inner()
+        {
+            await UniTask.Yield();
+            await UniTask.Yield();
+        }
+    }
+
+    [Benchmark(OperationsPerInvoke = InnerOps, Description = "UniTaskT")]
+    [BenchmarkCategory("UniTask")]
+    public async Task<int> ViaUniTaskT()
+    {
+        var sum = 0;
+        for (int i = 0; i < InnerOps; i++)
+        {
+            sum += await Inner(1, 2);
+        }
+        return sum;
+
+        static async UniTask<int> Inner(int x, int y)
+        {
+            int i = x;
+            await UniTask.Yield();
+            i *= y;
+            await UniTask.Yield();
+            return 5 * i;
+        }
+    }
+}
+
+public struct MyAwaiter : ICriticalNotifyCompletion
+{
+    public MyAwaiter GetAwaiter() => this;
+
+    public bool IsCompleted => false;
+
+    public void GetResult()
+    {
+    }
+
+    public void OnCompleted(Action continuation)
+    {
+        continuation();
+    }
+
+    public void UnsafeOnCompleted(Action continuation)
+    {
+        continuation();
+    }
+}
+
+public struct MyTestStateMachine : IAsyncStateMachine
+{
+    public void MoveNext()
+    {
+        //throw new NotImplementedException();
+
+
+
+
+    }
+
+    public void SetStateMachine(IAsyncStateMachine stateMachine)
+    {
+        //throw new NotImplementedException();
+    }
+}

src/UniTask.NetCoreSandbox/Program.cs

@@ -15,12 +15,132 @@ using System.Reactive.Concurrency;
 
 namespace NetCoreSandbox
 {
+    public class MySyncContext : SynchronizationContext
+    {
+        public MySyncContext()
+        {
+        }
+
+        public override void Post(SendOrPostCallback d, object state)
+        {
+            Console.WriteLine("Called SyncContext Post!");
+            base.Post(d, state);
+        }
+    }
+
     public class Text
     {
 
         public string text { get; set; }
     }
 
+    public class ZeroAllocAsyncAwaitInDotNetCore
+    {
+        public ValueTask<int> NanikaAsync(int x, int y)
+        {
+            return Core(this, x, y);
+
+            static async UniTask<int> Core(ZeroAllocAsyncAwaitInDotNetCore self, int x, int y)
+            {
+                // nanika suru...
+                await Task.Delay(TimeSpan.FromSeconds(x + y));
+
+                return 10;
+            }
+        }
+    }
+
+
+    public class TaskTestException : Exception
+    {
+
+    }
+
+
+    public struct TestAwaiter : ICriticalNotifyCompletion
+    {
+        readonly UniTaskStatus status;
+        readonly bool isCompleted;
+
+        public TestAwaiter(bool isCompleted, UniTaskStatus status)
+        {
+            this.isCompleted = isCompleted;
+            this.status = status;
+        }
+
+        public TestAwaiter GetAwaiter() => this;
+
+        public bool IsCompleted => isCompleted;
+
+        public void GetResult()
+        {
+            switch (status)
+            {
+                case UniTaskStatus.Faulted:
+                    throw new TaskTestException();
+                case UniTaskStatus.Canceled:
+                    throw new OperationCanceledException();
+                case UniTaskStatus.Pending:
+                case UniTaskStatus.Succeeded:
+                default:
+                    break;
+            }
+        }
+
+        public void OnCompleted(Action continuation)
+        {
+            ThreadPool.QueueUserWorkItem(_ => continuation(), null);
+        }
+
+        public void UnsafeOnCompleted(Action continuation)
+        {
+            ThreadPool.UnsafeQueueUserWorkItem(_ => continuation(), null);
+        }
+    }
+    public struct TestAwaiter<T> : ICriticalNotifyCompletion
+    {
+        readonly UniTaskStatus status;
+        readonly bool isCompleted;
+        readonly T value;
+
+        public TestAwaiter(bool isCompleted, UniTaskStatus status, T value)
+        {
+            this.isCompleted = isCompleted;
+            this.status = status;
+            this.value = value;
+        }
+
+        public TestAwaiter<T> GetAwaiter() => this;
+
+        public bool IsCompleted => isCompleted;
+
+        public T GetResult()
+        {
+            switch (status)
+            {
+                case UniTaskStatus.Faulted:
+                    throw new TaskTestException();
+                case UniTaskStatus.Canceled:
+                    throw new OperationCanceledException();
+                case UniTaskStatus.Pending:
+                case UniTaskStatus.Succeeded:
+                default:
+                    return value;
+            }
+        }
+
+        public void OnCompleted(Action continuation)
+        {
+            ThreadPool.QueueUserWorkItem(_ => continuation(), null);
+        }
+
+        public void UnsafeOnCompleted(Action continuation)
+        {
+            ThreadPool.UnsafeQueueUserWorkItem(_ => continuation(), null);
+        }
+    }
+
+
     public static partial class UnityUIComponentExtensions
     {
         public static void BindTo(this IUniTaskAsyncEnumerable<string> source, Text text)
@@ -86,27 +206,144 @@ namespace NetCoreSandbox
             await Task.Delay(10, cancellationToken);
         }
 
-
-
-        static void Main(string[] args)
+        public class MyDisposable : IDisposable
         {
+            public void Dispose()
+            {
 
-            var channel = Channel.CreateSingleConsumerUnbounded<int>();
+            }
+        }
 
-            // Observable.Range(1,10).CombineLatest(
+        static void Test()
+        {
+            var disp = new MyDisposable();
 
-            var cts = new CancellationTokenSource();
-
-            var token = cts.Token;
-
-            FooAsync(token).ForEachAsync(x => { }, token);
-
-
-            // Observable.Range(1,10).CombineLatest(
+            using var _ = new MyDisposable();
 
+            Console.WriteLine("tako");
         }
 
 
+        static async UniTask FooBarAsync()
+        {
+            await using (UniTask.ReturnToCurrentSynchronizationContext())
+            {
+                await UniTask.SwitchToThreadPool();
+
+
+
+
+            }
+        }
+
+
+
+
+        static async UniTask Aaa()
+        {
+            await FooBarAsync();
+
+            Console.WriteLine("FooBarAsync End");
+        }
+
+        static async UniTask WhereSelect()
+        {
+            await foreach (var item in UniTaskAsyncEnumerable.Range(1, 10)
+                .SelectAwait(async x =>
+                {
+                    await UniTask.Yield();
+                    return x;
+                })
+                .Where(x => x % 2 == 0))
+            {
+                Console.WriteLine(item);
+            }
+        }
+
+
+        static async Task Main(string[] args)
+        {
+#if !DEBUG
+         
+            
+
+
+            //await new AllocationCheck().ViaUniTaskVoid();
+            //Console.ReadLine();
+            BenchmarkDotNet.Running.BenchmarkSwitcher.FromAssembly(typeof(Program).Assembly).Run(args);
+
+            //await new ComparisonBenchmarks().ViaUniTaskT();
+            return;
+#endif
+            // await new AllocationCheck().ViaUniTaskVoid();
+
+            // AsyncTest().Forge
+
+            Console.WriteLine("A?");
+            var a = await new ZeroAllocAsyncAwaitInDotNetCore().NanikaAsync(1, 2);
+            Console.WriteLine("RET:" + a);
+            await WhereSelect();
+
+            SynchronizationContext.SetSynchronizationContext(new MySyncContext());
+
+            await Aaa();
+
+
+
+
+            //AsyncTest().Forget();
+
+            // AsyncTest().Forget();
+
+            ThreadPool.SetMinThreads(100, 100);
+
+            //List<UniTask<int>> list = new List<UniTask<int>>();
+            for (int i = 0; i < short.MaxValue; i++)
+            {
+                ////    list.Add(AsyncTest());
+                await YieldCore();
+            }
+            //await UniTask.WhenAll(list);
+
+            //Console.WriteLine("TOGO");
+
+            //var a = await AsyncTest();
+            //var b = AsyncTest();
+            //var c = AsyncTest();
+            await YieldCore();
+
+            //await b;
+            //await c;
+
+
+            //foreach (var item in Cysharp.Threading.Tasks.Internal.TaskPool.GetCacheSizeInfo())
+            //{
+            //    Console.WriteLine(item);
+            //}
+
+            Console.ReadLine();
+        }
+
+        static async UniTask YieldCore()
+        {
+            await UniTask.Yield();
+        }
+
+#pragma warning disable CS1998
+
+
+        static async UniTask<int> AsyncTest()
+        {
+            // empty 
+            await new TestAwaiter(false, UniTaskStatus.Succeeded);
+            await new TestAwaiter(true, UniTaskStatus.Succeeded);
+            await new TestAwaiter(false, UniTaskStatus.Succeeded);
+            return 10;
+        }
+
+
+
+#pragma warning restore CS1998
 
         void Foo()
         {

src/UniTask.NetCoreSandbox/QueueCheck.cs

@@ -0,0 +1,396 @@
+using BenchmarkDotNet.Attributes;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Threading;
+
+[Config(typeof(BenchmarkConfig))]
+public class QueueCheck
+{
+    Node node1 = new Node();
+    Node node2 = new Node();
+    Queue<Node> q1 = new Queue<Node>();
+    Stack<Node> s1 = new Stack<Node>();
+    ConcurrentQueue<Node> cq = new ConcurrentQueue<Node>();
+    ConcurrentStack<Node> cs = new ConcurrentStack<Node>();
+    static TaskPool<Node> pool;
+    static TaskPoolEqualNull<Node> poolEqualNull;
+    static TaskPoolClass<Node> poolClass = new TaskPoolClass<Node>();
+    static TaskPoolWithoutSize<Node> poolWithoutSize;
+    static TaskPoolWithoutLock<Node> poolWithoutLock;
+
+    [Benchmark]
+    public void Queue()
+    {
+        q1.Enqueue(node1);
+        q1.Enqueue(node1);
+        q1.TryDequeue(out _);
+        q1.TryDequeue(out _);
+    }
+
+    [Benchmark]
+    public void QueueLock()
+    {
+        lock (q1) { q1.Enqueue(node1); }
+        lock (q1) { q1.Enqueue(node1); }
+        lock (q1) { q1.TryDequeue(out _); }
+        lock (q1) { q1.TryDequeue(out _); }
+    }
+
+    [Benchmark]
+    public void Stack()
+    {
+        s1.Push(node1);
+        s1.Push(node2);
+        s1.TryPop(out _);
+        s1.TryPop(out _);
+    }
+
+    [Benchmark]
+    public void StackLock()
+    {
+        lock (s1) { s1.Push(node1); }
+        lock (s1) { s1.Push(node2); }
+        lock (s1) { s1.TryPop(out _); }
+        lock (s1) { s1.TryPop(out _); }
+    }
+
+    [Benchmark]
+    public void ConcurrentQueue()
+    {
+        cq.Enqueue(node1);
+        cq.Enqueue(node1);
+        cq.TryDequeue(out _);
+        cq.TryDequeue(out _);
+    }
+
+    [Benchmark]
+    public void ConcurrentStack()
+    {
+        cs.Push(node1);
+        cs.Push(node2);
+        cs.TryPop(out _);
+        cs.TryPop(out _);
+    }
+
+    [Benchmark]
+    public void TaskPool()
+    {
+        pool.TryPush(node1);
+        pool.TryPush(node2);
+        pool.TryPop(out _);
+        pool.TryPop(out _);
+    }
+
+    [Benchmark]
+    public void TaskPoolEqualNull()
+    {
+        poolEqualNull.TryPush(node1);
+        poolEqualNull.TryPush(node2);
+        poolEqualNull.TryPop(out _);
+        poolEqualNull.TryPop(out _);
+    }
+
+    [Benchmark]
+    public void TaskPoolClass()
+    {
+        poolClass.TryPush(node1);
+        poolClass.TryPush(node2);
+        poolClass.TryPop(out _);
+        poolClass.TryPop(out _);
+    }
+
+    [Benchmark]
+    public void TaskPoolWithoutSize()
+    {
+        poolWithoutSize.TryPush(node1);
+        poolWithoutSize.TryPush(node2);
+        poolWithoutSize.TryPop(out _);
+        poolWithoutSize.TryPop(out _);
+    }
+
+    [Benchmark]
+    public void TaskPoolWithoutLock()
+    {
+        poolWithoutLock.TryPush(node1);
+        poolWithoutLock.TryPush(node2);
+        poolWithoutLock.TryPop(out _);
+        poolWithoutLock.TryPop(out _);
+    }
+}
+
+public sealed class Node : ITaskPoolNode<Node>
+{
+    public Node NextNode { get; set; }
+}
+
+public interface ITaskPoolNode<T>
+{
+    T NextNode { get; set; }
+}
+
+// mutable struct, don't mark readonly.
+[StructLayout(LayoutKind.Auto)]
+public struct TaskPoolWithoutLock<T>
+    where T : class, ITaskPoolNode<T>
+{
+    int size;
+    T root;
+
+    public int Size => size;
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryPop(out T result)
+    {
+        //if (Interlocked.CompareExchange(ref gate, 1, 0) == 0)
+        {
+            var v = root;
+            if (!(v is null))
+            {
+                root = v.NextNode;
+                v.NextNode = null;
+                size--;
+                result = v;
+                //      Volatile.Write(ref gate, 0);
+                return true;
+            }
+
+            //Volatile.Write(ref gate, 0);
+        }
+        result = default;
+        return false;
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryPush(T item)
+    {
+        //if (Interlocked.CompareExchange(ref gate, 1, 0) == 0)
+        {
+            //if (size < TaskPool.MaxPoolSize)
+            {
+                item.NextNode = root;
+                root = item;
+                size++;
+                //      Volatile.Write(ref gate, 0);
+                return true;
+            }
+            //else
+            {
+                //  Volatile.Write(ref gate, 0);
+            }
+        }
+        //return false;
+    }
+}
+
+[StructLayout(LayoutKind.Auto)]
+public struct TaskPool<T>
+    where T : class, ITaskPoolNode<T>
+{
+    int gate;
+    int size;
+    T root;
+
+    public int Size => size;
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryPop(out T result)
+    {
+        if (Interlocked.CompareExchange(ref gate, 1, 0) == 0)
+        {
+            var v = root;
+            if (!(v is null))
+            {
+                root = v.NextNode;
+                v.NextNode = null;
+                size--;
+                result = v;
+                Volatile.Write(ref gate, 0);
+                return true;
+            }
+
+            Volatile.Write(ref gate, 0);
+        }
+        result = default;
+        return false;
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryPush(T item)
+    {
+        if (Interlocked.CompareExchange(ref gate, 1, 0) == 0)
+        {
+            //if (size < TaskPool.MaxPoolSize)
+            {
+                item.NextNode = root;
+                root = item;
+                size++;
+                Volatile.Write(ref gate, 0);
+                return true;
+            }
+            //else
+            {
+                //  Volatile.Write(ref gate, 0);
+            }
+        }
+        return false;
+    }
+}
+
+[StructLayout(LayoutKind.Auto)]
+public struct TaskPoolEqualNull<T>
+    where T : class, ITaskPoolNode<T>
+{
+    int gate;
+    int size;
+    T root;
+
+    public int Size => size;
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryPop(out T result)
+    {
+        if (Interlocked.CompareExchange(ref gate, 1, 0) == 0)
+        {
+            var v = root;
+            if (v != null)
+            {
+                root = v.NextNode;
+                v.NextNode = null;
+                size--;
+                result = v;
+                Volatile.Write(ref gate, 0);
+                return true;
+            }
+
+            Volatile.Write(ref gate, 0);
+        }
+        result = default;
+        return false;
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryPush(T item)
+    {
+        if (Interlocked.CompareExchange(ref gate, 1, 0) == 0)
+        {
+            //if (size < TaskPool.MaxPoolSize)
+            {
+                item.NextNode = root;
+                root = item;
+                size++;
+                Volatile.Write(ref gate, 0);
+                return true;
+            }
+            //else
+            {
+                //  Volatile.Write(ref gate, 0);
+            }
+        }
+        return false;
+    }
+}
+
+public class TaskPoolClass<T>
+    where T : class, ITaskPoolNode<T>
+{
+    int gate;
+    int size;
+    T root;
+
+    public int Size => size;
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryPop(out T result)
+    {
+        if (Interlocked.CompareExchange(ref gate, 1, 0) == 0)
+        {
+            var v = root;
+            if (!(v is null))
+            {
+                root = v.NextNode;
+                v.NextNode = null;
+                size--;
+                result = v;
+                Volatile.Write(ref gate, 0);
+                return true;
+            }
+
+            Volatile.Write(ref gate, 0);
+        }
+        result = default;
+        return false;
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryPush(T item)
+    {
+        if (Interlocked.CompareExchange(ref gate, 1, 0) == 0)
+        {
+            //if (size < TaskPool.MaxPoolSize)
+            {
+                item.NextNode = root;
+                root = item;
+                size++;
+                Volatile.Write(ref gate, 0);
+                return true;
+            }
+            //else
+            {
+                //  Volatile.Write(ref gate, 0);
+            }
+        }
+        return false;
+    }
+}
+
+[StructLayout(LayoutKind.Auto)]
+public struct TaskPoolWithoutSize<T>
+    where T : class, ITaskPoolNode<T>
+{
+    int gate;
+    T root;
+
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryPop(out T result)
+    {
+        if (Interlocked.CompareExchange(ref gate, 1, 0) == 0)
+        {
+            var v = root;
+            if (!(v is null))
+            {
+                root = v.NextNode;
+                v.NextNode = null;
+                result = v;
+                Volatile.Write(ref gate, 0);
+                return true;
+            }
+
+            Volatile.Write(ref gate, 0);
+        }
+        result = default;
+        return false;
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryPush(T item)
+    {
+        if (Interlocked.CompareExchange(ref gate, 1, 0) == 0)
+        {
+            //if (size < TaskPool.MaxPoolSize)
+            {
+                item.NextNode = root;
+                root = item;
+                Volatile.Write(ref gate, 0);
+                return true;
+            }
+            //else
+            {
+                //  Volatile.Write(ref gate, 0);
+            }
+        }
+        return false;
+    }
+}

src/UniTask.NetCoreSandbox/UniTask.NetCoreSandbox.csproj

@@ -7,6 +7,8 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="BenchmarkDotNet" Version="0.12.1" />
+    <PackageReference Include="PooledAwait" Version="1.0.49" />
     <PackageReference Include="System.Interactive.Async" Version="4.1.1" />
     <PackageReference Include="System.Reactive" Version="4.4.1" />
   </ItemGroup>

src/UniTask.NetCoreTests/TaskBuilderCases.cs

@@ -0,0 +1,301 @@
+#pragma warning disable CS1998 
+
+using Cysharp.Threading.Tasks;
+using FluentAssertions;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using System.Threading.Channels;
+using Cysharp.Threading.Tasks.Linq;
+using System.Threading.Tasks;
+using Xunit;
+using System.Runtime.CompilerServices;
+
+namespace NetCoreTests
+{
+    public class UniTaskBuilderTest
+    {
+        [Fact]
+        public async Task Empty()
+        {
+            await Core();
+
+            static async UniTask Core()
+            {
+            }
+        }
+
+        [Fact]
+        public async Task EmptyThrow()
+        {
+            await Assert.ThrowsAsync<TaskTestException>(async () => await Core());
+
+            static async UniTask Core()
+            {
+                throw new TaskTestException();
+            }
+        }
+
+        [Fact]
+        public async Task Task_Done()
+        {
+            await Core();
+
+            static async UniTask Core()
+            {
+                await new TestAwaiter(true, UniTaskStatus.Succeeded);
+            }
+        }
+
+        [Fact]
+        public async Task Task_Fail()
+        {
+            await Assert.ThrowsAsync<TaskTestException>(async () => await Core());
+
+            static async UniTask Core()
+            {
+                await new TestAwaiter(true, UniTaskStatus.Faulted);
+            }
+        }
+
+        [Fact]
+        public async Task Task_Cancel()
+        {
+            await Assert.ThrowsAsync<OperationCanceledException>(async () => await Core());
+
+            static async UniTask Core()
+            {
+                await new TestAwaiter(true, UniTaskStatus.Canceled);
+            }
+        }
+
+        [Fact]
+        public async Task AwaitUnsafeOnCompletedCall_Task_SetResult()
+        {
+            await Core();
+
+            static async UniTask Core()
+            {
+                await new TestAwaiter(false, UniTaskStatus.Succeeded);
+                await new TestAwaiter(false, UniTaskStatus.Succeeded);
+                await new TestAwaiter(false, UniTaskStatus.Succeeded);
+            }
+        }
+
+        [Fact]
+        public async Task AwaitUnsafeOnCompletedCall_Task_SetException()
+        {
+            await Assert.ThrowsAsync<TaskTestException>(async () => await Core());
+
+            static async UniTask Core()
+            {
+                await new TestAwaiter(false, UniTaskStatus.Succeeded);
+                await new TestAwaiter(false, UniTaskStatus.Faulted);
+                throw new InvalidOperationException();
+            }
+        }
+
+        [Fact]
+        public async Task AwaitUnsafeOnCompletedCall_Task_SetCancelException()
+        {
+            await Assert.ThrowsAsync<OperationCanceledException>(async () => await Core());
+
+            static async UniTask Core()
+            {
+                await new TestAwaiter(false, UniTaskStatus.Succeeded);
+                await new TestAwaiter(false, UniTaskStatus.Canceled);
+                throw new InvalidOperationException();
+            }
+        }
+    }
+
+    public class UniTask_T_BuilderTest
+    {
+        [Fact]
+        public async Task Empty()
+        {
+            (await Core()).Should().Be(10);
+
+            static async UniTask<int> Core()
+            {
+                return 10;
+            }
+        }
+
+        [Fact]
+        public async Task EmptyThrow()
+        {
+            await Assert.ThrowsAsync<TaskTestException>(async () => await Core());
+
+            static async UniTask<int> Core()
+            {
+                throw new TaskTestException();
+            }
+        }
+
+        [Fact]
+        public async Task Task_Done()
+        {
+            (await Core()).Should().Be(10);
+
+            static async UniTask<int> Core()
+            {
+                return await new TestAwaiter<int>(true, UniTaskStatus.Succeeded, 10);
+            }
+        }
+
+        [Fact]
+        public async Task Task_Fail()
+        {
+            await Assert.ThrowsAsync<TaskTestException>(async () => await Core());
+
+            static async UniTask<int> Core()
+            {
+                return await new TestAwaiter<int>(true, UniTaskStatus.Faulted, 10);
+            }
+        }
+
+        [Fact]
+        public async Task Task_Cancel()
+        {
+            await Assert.ThrowsAsync<OperationCanceledException>(async () => await Core());
+
+            static async UniTask<int> Core()
+            {
+                return await new TestAwaiter<int>(true, UniTaskStatus.Canceled, 10);
+            }
+        }
+
+        [Fact]
+        public async Task AwaitUnsafeOnCompletedCall_Task_SetResult()
+        {
+            (await Core()).Should().Be(6);
+
+            static async UniTask<int> Core()
+            {
+                var sum = 0;
+                sum += await new TestAwaiter<int>(false, UniTaskStatus.Succeeded, 1);
+                sum += await new TestAwaiter<int>(false, UniTaskStatus.Succeeded, 2);
+                sum += await new TestAwaiter<int>(false, UniTaskStatus.Succeeded, 3);
+                return sum;
+            }
+        }
+
+        [Fact]
+        public async Task AwaitUnsafeOnCompletedCall_Task_SetException()
+        {
+            await Assert.ThrowsAsync<TaskTestException>(async () => await Core());
+
+            static async UniTask<int> Core()
+            {
+                await new TestAwaiter<int>(false, UniTaskStatus.Succeeded, 10);
+                await new TestAwaiter<int>(false, UniTaskStatus.Faulted, 10);
+                throw new InvalidOperationException();
+            }
+        }
+
+        [Fact]
+        public async Task AwaitUnsafeOnCompletedCall_Task_SetCancelException()
+        {
+            await Assert.ThrowsAsync<OperationCanceledException>(async () => await Core());
+
+            static async UniTask<int> Core()
+            {
+                await new TestAwaiter<int>(false, UniTaskStatus.Succeeded, 10);
+                await new TestAwaiter<int>(false, UniTaskStatus.Canceled, 10);
+                throw new InvalidOperationException();
+            }
+        }
+    }
+
+    public class TaskTestException : Exception
+    {
+
+    }
+
+    public struct TestAwaiter : ICriticalNotifyCompletion
+    {
+        readonly UniTaskStatus status;
+        readonly bool isCompleted;
+
+        public TestAwaiter(bool isCompleted, UniTaskStatus status)
+        {
+            this.isCompleted = isCompleted;
+            this.status = status;
+        }
+
+        public TestAwaiter GetAwaiter() => this;
+
+        public bool IsCompleted => isCompleted;
+
+        public void GetResult()
+        {
+            switch (status)
+            {
+                case UniTaskStatus.Faulted:
+                    throw new TaskTestException();
+                case UniTaskStatus.Canceled:
+                    throw new OperationCanceledException();
+                case UniTaskStatus.Pending:
+                case UniTaskStatus.Succeeded:
+                default:
+                    break;
+            }
+        }
+
+        public void OnCompleted(Action continuation)
+        {
+            ThreadPool.QueueUserWorkItem(_ => continuation(), null);
+        }
+
+        public void UnsafeOnCompleted(Action continuation)
+        {
+            ThreadPool.UnsafeQueueUserWorkItem(_ => continuation(), null);
+        }
+    }
+
+    public struct TestAwaiter<T> : ICriticalNotifyCompletion
+    {
+        readonly UniTaskStatus status;
+        readonly bool isCompleted;
+        readonly T value;
+
+        public TestAwaiter(bool isCompleted, UniTaskStatus status, T value)
+        {
+            this.isCompleted = isCompleted;
+            this.status = status;
+            this.value = value;
+        }
+
+        public TestAwaiter<T> GetAwaiter() => this;
+
+        public bool IsCompleted => isCompleted;
+
+        public T GetResult()
+        {
+            switch (status)
+            {
+                case UniTaskStatus.Faulted:
+                    throw new TaskTestException();
+                case UniTaskStatus.Canceled:
+                    throw new OperationCanceledException();
+                case UniTaskStatus.Pending:
+                case UniTaskStatus.Succeeded:
+                default:
+                    return value;
+            }
+        }
+
+        public void OnCompleted(Action continuation)
+        {
+            ThreadPool.QueueUserWorkItem(_ => continuation(), null);
+        }
+
+        public void UnsafeOnCompleted(Action continuation)
+        {
+            ThreadPool.UnsafeQueueUserWorkItem(_ => continuation(), null);
+        }
+    }
+}

src/UniTask.NetCoreTests/TriggerEventTest.cs

@@ -0,0 +1,637 @@
+using Cysharp.Threading.Tasks;
+using FluentAssertions;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using System.Threading.Channels;
+using Cysharp.Threading.Tasks.Linq;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace NetCoreTests
+{
+    public class TriggerEventTest
+    {
+        [Fact]
+        public void SimpleAdd()
+        {
+            var ev = new TriggerEvent<int>();
+
+            // do nothing
+            ev.SetResult(0);
+            ev.SetError(null);
+            ev.SetCompleted();
+            ev.SetCanceled(default);
+
+            {
+                var one = new TestEvent(1);
+
+                ev.Add(one);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+
+                ev.SetCompleted();
+
+                one.CompletedCalled.Count.Should().Be(1);
+
+                // do nothing
+                ev.SetResult(0);
+                ev.SetError(null);
+                ev.SetCompleted();
+                ev.SetCanceled(default);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                one.CompletedCalled.Count.Should().Be(1);
+            }
+            // after removed, onemore
+            {
+                var one = new TestEvent(1);
+
+                ev.Add(one);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+
+                ev.SetCompleted();
+
+                one.CompletedCalled.Count.Should().Be(1);
+
+                // do nothing
+                ev.SetResult(0);
+                ev.SetError(null);
+                ev.SetCompleted();
+                ev.SetCanceled(default);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                one.CompletedCalled.Count.Should().Be(1);
+            }
+        }
+
+        [Fact]
+        public void AddFour()
+        {
+            var ev = new TriggerEvent<int>();
+
+            // do nothing
+            ev.SetResult(0);
+            ev.SetError(null);
+            ev.SetCompleted();
+            ev.SetCanceled(default);
+
+            {
+                var one = new TestEvent(1);
+                var two = new TestEvent(2);
+                var three = new TestEvent(3);
+                var four = new TestEvent(4);
+
+                ev.Add(one);
+                ev.Add(two);
+                ev.Add(three);
+                ev.Add(four);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                four.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+
+                ev.SetCompleted();
+
+                one.CompletedCalled.Count.Should().Be(1);
+                two.CompletedCalled.Count.Should().Be(1);
+                three.CompletedCalled.Count.Should().Be(1);
+
+
+                // do nothing
+                ev.SetResult(0);
+                ev.SetError(null);
+                ev.SetCompleted();
+                ev.SetCanceled(default);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                one.CompletedCalled.Count.Should().Be(1);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                three.CompletedCalled.Count.Should().Be(1);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                three.CompletedCalled.Count.Should().Be(1);
+            }
+
+            // after removed, onemore.
+            {
+                var one = new TestEvent(1);
+                var two = new TestEvent(2);
+                var three = new TestEvent(3);
+                var four = new TestEvent(4);
+
+                ev.Add(one);
+                ev.Add(two);
+                ev.Add(three);
+                ev.Add(four);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+                ev.Add(four);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                four.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+
+                ev.SetCompleted();
+
+                one.CompletedCalled.Count.Should().Be(1);
+                two.CompletedCalled.Count.Should().Be(1);
+                three.CompletedCalled.Count.Should().Be(1);
+
+
+                // do nothing
+                ev.SetResult(0);
+                ev.SetError(null);
+                ev.SetCompleted();
+                ev.SetCanceled(default);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                one.CompletedCalled.Count.Should().Be(1);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                three.CompletedCalled.Count.Should().Be(1);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                three.CompletedCalled.Count.Should().Be(1);
+            }
+        }
+
+
+        [Fact]
+        public void OneRemove()
+        {
+            var ev = new TriggerEvent<int>();
+            {
+                var one = new TestEvent(1);
+                var two = new TestEvent(2);
+                var three = new TestEvent(3);
+
+                ev.Add(one);
+                ev.Add(two);
+                ev.Add(three);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+
+                ev.Remove(one);
+
+                ev.SetResult(40);
+                ev.SetResult(50);
+                ev.SetResult(60);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30, 40, 50, 60);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30, 40, 50, 60);
+            }
+        }
+        [Fact]
+        public void TwoRemove()
+        {
+            var ev = new TriggerEvent<int>();
+            {
+                var one = new TestEvent(1);
+                var two = new TestEvent(2);
+                var three = new TestEvent(3);
+
+                ev.Add(one);
+                ev.Add(two);
+                ev.Add(three);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+
+                ev.Remove(two);
+
+                ev.SetResult(40);
+                ev.SetResult(50);
+                ev.SetResult(60);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30, 40, 50, 60);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30, 40, 50, 60);
+            }
+        }
+        [Fact]
+        public void ThreeRemove()
+        {
+            var ev = new TriggerEvent<int>();
+            {
+                var one = new TestEvent(1);
+                var two = new TestEvent(2);
+                var three = new TestEvent(3);
+
+                ev.Add(one);
+                ev.Add(two);
+                ev.Add(three);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+
+                ev.Remove(three);
+
+                ev.SetResult(40);
+                ev.SetResult(50);
+                ev.SetResult(60);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30, 40, 50, 60);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30, 40, 50, 60);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+            }
+        }
+
+        [Fact]
+        public void RemoveSelf()
+        {
+            new RemoveMe().Run1();
+            new RemoveMe().Run2();
+            new RemoveMe().Run3();
+        }
+
+        [Fact]
+        public void RemoveNextInIterating()
+        {
+            new RemoveNext().Run1();
+            new RemoveNext().Run2();
+            new RemoveNext().Run3();
+        }
+
+        [Fact]
+        public void RemoveNextNextTest()
+        {
+            new RemoveNextNext().Run1();
+            new RemoveNextNext().Run2();
+        }
+
+
+        [Fact]
+        public void AddTest()
+        {
+            new AddMe().Run1();
+            new AddMe().Run2();
+        }
+
+        public class RemoveMe
+        {
+            TriggerEvent<int> ev;
+
+            public void Run1()
+            {
+                TestEvent one = default;
+                one = new TestEvent(1, () => ev.Remove(one));
+
+                var two = new TestEvent(2);
+                var three = new TestEvent(3);
+
+                ev.Add(one);
+                ev.Add(two);
+                ev.Add(three);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+            }
+
+            public void Run2()
+            {
+                TestEvent one = default;
+                one = new TestEvent(1, () => ev.Remove(one));
+
+                var two = new TestEvent(2);
+                var three = new TestEvent(3);
+
+                ev.Add(two);
+                ev.Add(one); // add second.
+                ev.Add(three);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+            }
+
+            public void Run3()
+            {
+                TestEvent one = default;
+                one = new TestEvent(1, () => ev.Remove(one));
+
+                var two = new TestEvent(2);
+                var three = new TestEvent(3);
+
+                ev.Add(two);
+                ev.Add(three);
+                ev.Add(one); // add thired.
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10);
+                two.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+            }
+        }
+
+        public class RemoveNext
+        {
+            TriggerEvent<int> ev;
+
+            public void Run1()
+            {
+                TestEvent one = default;
+                TestEvent two = default;
+                TestEvent three = default;
+                one = new TestEvent(1, () => ev.Remove(two));
+                two = new TestEvent(2);
+                three = new TestEvent(3);
+
+                ev.Add(one);
+                ev.Add(two);
+                ev.Add(three);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                two.NextCalled.Count.Should().Be(0);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+            }
+
+            public void Run2()
+            {
+                TestEvent one = default;
+                TestEvent two = default;
+                TestEvent three = default;
+                one = new TestEvent(1, () => ev.Remove(two));
+                two = new TestEvent(2);
+                three = new TestEvent(3);
+
+                ev.Add(two);
+                ev.Add(one); // add second
+                ev.Add(three);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                two.NextCalled.Should().BeEquivalentTo(10);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+            }
+
+            public void Run3()
+            {
+                TestEvent one = default;
+                TestEvent two = default;
+                TestEvent three = default;
+                one = new TestEvent(1, () => ev.Remove(two));
+                two = new TestEvent(2);
+                three = new TestEvent(3);
+
+                ev.Add(two);
+                ev.Add(three);
+                ev.Add(one); // add thired.
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                two.NextCalled.Should().BeEquivalentTo(10);
+                three.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+            }
+        }
+
+        public class RemoveNextNext
+        {
+            TriggerEvent<int> ev;
+
+            public void Run1()
+            {
+                TestEvent one = default;
+                TestEvent two = default;
+                TestEvent three = default;
+                TestEvent four = default;
+                one = new TestEvent(1, () => { ev.Remove(two); ev.Remove(three); });
+                two = new TestEvent(2);
+                three = new TestEvent(3);
+                four = new TestEvent(4);
+
+                ev.Add(one);
+                ev.Add(two);
+                ev.Add(three);
+                ev.Add(four);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+                two.NextCalled.Count.Should().Be(0);
+                three.NextCalled.Count.Should().Be(0);
+                four.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+            }
+
+            public void Run2()
+            {
+                TestEvent one = default;
+                TestEvent two = default;
+                TestEvent three = default;
+                TestEvent four = default;
+                one = new TestEvent(1, () => { ev.Remove(one); ev.Remove(two); ev.Remove(three); });
+                two = new TestEvent(2);
+                three = new TestEvent(3);
+                four = new TestEvent(4);
+
+                ev.Add(one);
+                ev.Add(two);
+                ev.Add(three);
+                ev.Add(four);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+
+                one.NextCalled.Should().BeEquivalentTo(10);
+                two.NextCalled.Count.Should().Be(0);
+                three.NextCalled.Count.Should().Be(0);
+                four.NextCalled.Should().BeEquivalentTo(10, 20, 30);
+            }
+
+
+        }
+
+        public class AddMe
+        {
+            TriggerEvent<int> ev;
+
+            public void Run1()
+            {
+                TestEvent one = default;
+                TestEvent two = default;
+                TestEvent three = default;
+                TestEvent four = default;
+
+                one = new TestEvent(1, () =>
+                {
+                    if (two == null)
+                    {
+                        ev.Add(two = new TestEvent(2));
+                    }
+                    else if (three == null)
+                    {
+                        ev.Add(three = new TestEvent(3));
+                    }
+                    else if (four == null)
+                    {
+                        ev.Add(four = new TestEvent(4));
+                    }
+                });
+
+                ev.Add(one);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+                ev.SetResult(40);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30, 40);
+                two.NextCalled.Should().BeEquivalentTo(20, 30, 40);
+                three.NextCalled.Should().BeEquivalentTo(30, 40);
+                four.NextCalled.Should().BeEquivalentTo(40);
+            }
+
+            public void Run2()
+            {
+                TestEvent one = default;
+                TestEvent two = default;
+                TestEvent three = default;
+                TestEvent four = default;
+
+                one = new TestEvent(1, () =>
+                {
+                    if (two == null)
+                    {
+                        ev.Add(two = new TestEvent(2, () =>
+                        {
+                            if (three == null)
+                            {
+                                ev.Add(three = new TestEvent(3, () =>
+                                {
+                                    if (four == null)
+                                    {
+                                        ev.Add(four = new TestEvent(4));
+                                    }
+                                }));
+                            }
+                        }));
+                    }
+                });
+
+                ev.Add(one);
+
+                ev.SetResult(10);
+                ev.SetResult(20);
+                ev.SetResult(30);
+                ev.SetResult(40);
+
+                one.NextCalled.Should().BeEquivalentTo(10, 20, 30, 40);
+                two.NextCalled.Should().BeEquivalentTo(20, 30, 40);
+                three.NextCalled.Should().BeEquivalentTo(30, 40);
+                four.NextCalled.Should().BeEquivalentTo(40);
+            }
+        }
+    }
+
+    public class TestEvent : ITriggerHandler<int>
+    {
+        public readonly int Id;
+        readonly Action iteratingEvent;
+
+        public TestEvent(int id)
+        {
+            this.Id = id;
+        }
+
+        public TestEvent(int id, Action iteratingEvent)
+        {
+            this.Id = id;
+            this.iteratingEvent = iteratingEvent;
+        }
+
+        public List<int> NextCalled = new List<int>();
+        public List<Exception> ErrorCalled = new List<Exception>();
+        public List<object> CompletedCalled = new List<object>();
+        public List<CancellationToken> CancelCalled = new List<CancellationToken>();
+
+        public ITriggerHandler<int> Prev { get; set; }
+        public ITriggerHandler<int> Next { get; set; }
+
+        public void OnCanceled(CancellationToken cancellationToken)
+        {
+            CancelCalled.Add(cancellationToken);
+
+        }
+
+        public void OnCompleted()
+        {
+            CompletedCalled.Add(new object());
+        }
+
+        public void OnError(Exception ex)
+        {
+            ErrorCalled.Add(ex);
+        }
+
+        public void OnNext(int value)
+        {
+            NextCalled.Add(value);
+            iteratingEvent?.Invoke();
+        }
+
+        public override string ToString()
+        {
+            return Id.ToString();
+        }
+    }
+
+
+}

src/UniTask/Assets/Editor/EditorRunnerChecker.cs

@@ -0,0 +1,30 @@
+#if UNITY_EDITOR
+
+using Cysharp.Threading.Tasks;
+using System;
+using System.IO;
+using System.Linq;
+using UnityEditor;
+using UnityEngine;
+using UnityEngine.Networking;
+
+public static class EditorRunnerChecker
+{
+    [MenuItem("Tools/UniTaskEditorRunnerChecker")]
+    public static void RunUniTaskAsync()
+    {
+        RunCore().Forget();
+    }
+
+    static async UniTaskVoid RunCore()
+    {
+        Debug.Log("Start");
+
+        var r = await UnityWebRequest.Get("https://bing.com/").SendWebRequest().ToUniTask();
+        Debug.Log(r.downloadHandler.text.Substring(0, 100));
+
+        Debug.Log("End");
+    }
+}
+
+#endif

src/UniTask/Assets/Editor/EditorRunnerChecker.cs.meta

@@ -1,5 +1,5 @@
 fileFormatVersion: 2
-guid: fcb1f7467a3e2b64c8a016c8aee2f9b4
+guid: e51b78c06cb410f42b36e0af9de3b065
 MonoImporter:
   externalObjects: {}
   serializedVersion: 2

src/UniTask/Assets/Plugins/UniTask/Runtime/AsyncReactiveProperty.cs

@@ -1,5 +1,4 @@
-using Cysharp.Threading.Tasks.Linq;
-using System;
+using System;
 using System.Threading;
 
 namespace Cysharp.Threading.Tasks
@@ -120,6 +119,9 @@ namespace Cysharp.Threading.Tasks
 
             public T Current => value;
 
+            ITriggerHandler<T> ITriggerHandler<T>.Prev { get; set; }
+            ITriggerHandler<T> ITriggerHandler<T>.Next { get; set; }
+
             public UniTask<bool> MoveNextAsync()
             {
                 // raise latest value on first call.
@@ -300,6 +302,8 @@ namespace Cysharp.Threading.Tasks
             }
 
             public T Current => value;
+            ITriggerHandler<T> ITriggerHandler<T>.Prev { get; set; }
+            ITriggerHandler<T> ITriggerHandler<T>.Next { get; set; }
 
             public UniTask<bool> MoveNextAsync()
             {

src/UniTask/Assets/Plugins/UniTask/Runtime/AsyncUnit.cs

@@ -4,7 +4,7 @@ using System;
 
 namespace Cysharp.Threading.Tasks
 {
-    public struct AsyncUnit : IEquatable<AsyncUnit>
+    public readonly struct AsyncUnit : IEquatable<AsyncUnit>
     {
         public static readonly AsyncUnit Default = new AsyncUnit();
 

src/UniTask/Assets/Plugins/UniTask/Runtime/Channel.cs

@@ -368,8 +368,8 @@ namespace Cysharp.Threading.Tasks
                 readonly SingleConsumerUnboundedChannelReader parent;
                 CancellationToken cancellationToken1;
                 CancellationToken cancellationToken2;
-                CancellationTokenRegistration CancellationTokenRegistration1;
-                CancellationTokenRegistration CancellationTokenRegistration2;
+                CancellationTokenRegistration cancellationTokenRegistration1;
+                CancellationTokenRegistration cancellationTokenRegistration2;
 
                 T current;
                 bool cacheValue;
@@ -395,12 +395,12 @@ namespace Cysharp.Threading.Tasks
 
                     if (this.cancellationToken1.CanBeCanceled)
                     {
-                        this.cancellationToken1.RegisterWithoutCaptureExecutionContext(CancellationCallback1Delegate, this);
+                        this.cancellationTokenRegistration1 =  this.cancellationToken1.RegisterWithoutCaptureExecutionContext(CancellationCallback1Delegate, this);
                     }
 
                     if (this.cancellationToken2.CanBeCanceled)
                     {
-                        this.cancellationToken2.RegisterWithoutCaptureExecutionContext(CancellationCallback2Delegate, this);
+                        this.cancellationTokenRegistration2 = this.cancellationToken2.RegisterWithoutCaptureExecutionContext(CancellationCallback2Delegate, this);
                     }
 
                     running = true;
@@ -428,8 +428,8 @@ namespace Cysharp.Threading.Tasks
 
                 public UniTask DisposeAsync()
                 {
-                    CancellationTokenRegistration1.Dispose();
-                    CancellationTokenRegistration2.Dispose();
+                    cancellationTokenRegistration1.Dispose();
+                    cancellationTokenRegistration2.Dispose();
                     return default;
                 }
 

src/UniTask/Assets/Plugins/UniTask/Runtime/CompilerServices/AsyncUniTaskMethodBuilder.cs

@@ -12,9 +12,8 @@ namespace Cysharp.Threading.Tasks.CompilerServices
     [StructLayout(LayoutKind.Auto)]
     public struct AsyncUniTaskMethodBuilder
     {
-        // cache items.
-        AutoResetUniTaskCompletionSource promise;
-        IMoveNextRunner runner;
+        internal IStateMachineRunnerPromise runnerPromise;
+        Exception ex;
 
         // 1. Static Create method.
         [DebuggerHidden]
@@ -31,98 +30,81 @@ namespace Cysharp.Threading.Tasks.CompilerServices
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
             get
             {
-                if (promise != null)
+                if (runnerPromise != null)
                 {
-                    return promise.Task;
+                    return runnerPromise.Task;
                 }
-
-                if (runner == null)
+                else if (ex != null)
+                {
+                    return UniTask.FromException(ex);
+                }
+                else
                 {
                     return UniTask.CompletedTask;
                 }
-
-                promise = AutoResetUniTaskCompletionSource.Create();
-                return promise.Task;
             }
         }
 
         // 3. SetException
         [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void SetException(Exception exception)
         {
-            // runner is finished, return first.
-            if (runner != null)
+            if (runnerPromise == null)
             {
-                runner.Return();
-                runner = null;
-            }
-
-            if (promise != null)
-            {
-                promise.TrySetException(exception);
+                ex = exception;
             }
             else
             {
-                promise = AutoResetUniTaskCompletionSource.CreateFromException(exception, out _);
+                runnerPromise.SetException(exception);
             }
         }
 
         // 4. SetResult
         [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void SetResult()
         {
-            // runner is finished, return first.
-            if (runner != null)
+            if (runnerPromise != null)
             {
-                runner.Return();
-                runner = null;
-            }
-
-            if (promise != null)
-            {
-                promise.TrySetResult();
+                runnerPromise.SetResult();
             }
         }
 
         // 5. AwaitOnCompleted
         [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void AwaitOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine)
             where TAwaiter : INotifyCompletion
             where TStateMachine : IAsyncStateMachine
         {
-            if (promise == null)
+            if (runnerPromise == null)
             {
-                promise = AutoResetUniTaskCompletionSource.Create();
-            }
-            if (runner == null)
-            {
-                runner = MoveNextRunner<TStateMachine>.Create(ref stateMachine);
+                AsyncUniTask<TStateMachine>.SetStateMachine(ref this, ref stateMachine);
             }
 
-            awaiter.OnCompleted(runner.CallMoveNext);
+            awaiter.OnCompleted(runnerPromise.MoveNext);
         }
 
         // 6. AwaitUnsafeOnCompleted
         [DebuggerHidden]
         [SecuritySafeCritical]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void AwaitUnsafeOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine)
             where TAwaiter : ICriticalNotifyCompletion
             where TStateMachine : IAsyncStateMachine
         {
-            if (promise == null)
+            if (runnerPromise == null)
             {
-                promise = AutoResetUniTaskCompletionSource.Create();
-            }
-            if (runner == null)
-            {
-                runner = MoveNextRunner<TStateMachine>.Create(ref stateMachine);
+                AsyncUniTask<TStateMachine>.SetStateMachine(ref this, ref stateMachine);
             }
 
-            awaiter.OnCompleted(runner.CallMoveNext);
+            awaiter.UnsafeOnCompleted(runnerPromise.MoveNext);
         }
 
         // 7. Start
         [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Start<TStateMachine>(ref TStateMachine stateMachine)
             where TStateMachine : IAsyncStateMachine
         {
@@ -156,9 +138,8 @@ namespace Cysharp.Threading.Tasks.CompilerServices
     [StructLayout(LayoutKind.Auto)]
     public struct AsyncUniTaskMethodBuilder<T>
     {
-        // cache items.
-        AutoResetUniTaskCompletionSource<T> promise;
-        IMoveNextRunner runner;
+        internal IStateMachineRunnerPromise<T> runnerPromise;
+        Exception ex;
         T result;
 
         // 1. Static Create method.
@@ -170,106 +151,91 @@ namespace Cysharp.Threading.Tasks.CompilerServices
         }
 
         // 2. TaskLike Task property.
-        [DebuggerHidden]
         public UniTask<T> Task
         {
+            [DebuggerHidden]
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
             get
             {
-                if (promise != null)
+                if (runnerPromise != null)
                 {
-                    return promise.Task;
+                    return runnerPromise.Task;
                 }
-
-                if (runner == null)
+                else if (ex != null)
+                {
+                    return UniTask.FromException<T>(ex);
+                }
+                else
                 {
                     return UniTask.FromResult(result);
                 }
-
-                promise = AutoResetUniTaskCompletionSource<T>.Create();
-                return promise.Task;
             }
         }
 
         // 3. SetException
         [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void SetException(Exception exception)
         {
-            // runner is finished, return first.
-            if (runner != null)
+            if (runnerPromise == null)
             {
-                runner.Return();
-                runner = null;
-            }
-
-            if (promise == null)
-            {
-                promise = AutoResetUniTaskCompletionSource<T>.CreateFromException(exception, out _);
+                ex = exception;
             }
             else
             {
-                promise.TrySetException(exception);
+                runnerPromise.SetException(exception);
             }
         }
 
         // 4. SetResult
         [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void SetResult(T result)
         {
-            // runner is finished, return first.
-            if (runner != null)
-            {
-                runner.Return();
-                runner = null;
-            }
-
-            if (promise == null)
+            if (runnerPromise == null)
             {
                 this.result = result;
-                return;
             }
-
-            promise.TrySetResult(result);
+            else
+            {
+                runnerPromise.SetResult(result);
+            }
         }
 
         // 5. AwaitOnCompleted
         [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void AwaitOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine)
             where TAwaiter : INotifyCompletion
             where TStateMachine : IAsyncStateMachine
         {
-            if (promise == null)
+            if (runnerPromise == null)
             {
-                promise = AutoResetUniTaskCompletionSource<T>.Create();
-            }
-            if (runner == null)
-            {
-                runner = MoveNextRunner<TStateMachine>.Create(ref stateMachine);
+                AsyncUniTask<TStateMachine, T>.SetStateMachine(ref this, ref stateMachine);
             }
 
-            awaiter.OnCompleted(runner.CallMoveNext);
+            awaiter.OnCompleted(runnerPromise.MoveNext);
         }
 
         // 6. AwaitUnsafeOnCompleted
         [DebuggerHidden]
         [SecuritySafeCritical]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void AwaitUnsafeOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine)
             where TAwaiter : ICriticalNotifyCompletion
             where TStateMachine : IAsyncStateMachine
         {
-            if (promise == null)
+            if (runnerPromise == null)
             {
-                promise = AutoResetUniTaskCompletionSource<T>.Create();
-            }
-            if (runner == null)
-            {
-                runner = MoveNextRunner<TStateMachine>.Create(ref stateMachine);
+                AsyncUniTask<TStateMachine, T>.SetStateMachine(ref this, ref stateMachine);
             }
 
-            awaiter.OnCompleted(runner.CallMoveNext);
+            awaiter.UnsafeOnCompleted(runnerPromise.MoveNext);
         }
 
         // 7. Start
         [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Start<TStateMachine>(ref TStateMachine stateMachine)
             where TStateMachine : IAsyncStateMachine
         {

src/UniTask/Assets/Plugins/UniTask/Runtime/CompilerServices/AsyncUniTaskVoidMethodBuilder.cs

@@ -4,13 +4,15 @@
 using System;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 using System.Security;
 
 namespace Cysharp.Threading.Tasks.CompilerServices
 {
+    [StructLayout(LayoutKind.Auto)]
     public struct AsyncUniTaskVoidMethodBuilder
     {
-        IMoveNextRunner runner;
+        internal IStateMachineRunner runner;
 
         // 1. Static Create method.
         [DebuggerHidden]
@@ -33,6 +35,7 @@ namespace Cysharp.Threading.Tasks.CompilerServices
 
         // 3. SetException
         [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void SetException(Exception exception)
         {
             // runner is finished, return first.
@@ -47,6 +50,7 @@ namespace Cysharp.Threading.Tasks.CompilerServices
 
         // 4. SetResult
         [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void SetResult()
         {
             // runner is finished, return.
@@ -59,31 +63,33 @@ namespace Cysharp.Threading.Tasks.CompilerServices
 
         // 5. AwaitOnCompleted
         [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void AwaitOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine)
             where TAwaiter : INotifyCompletion
             where TStateMachine : IAsyncStateMachine
         {
             if (runner == null)
             {
-                runner = MoveNextRunner<TStateMachine>.Create(ref stateMachine);
+                AsyncUniTaskVoid<TStateMachine>.SetStateMachine(ref this, ref stateMachine);
             }
 
-            awaiter.OnCompleted(runner.CallMoveNext);
+            awaiter.OnCompleted(runner.MoveNext);
         }
 
         // 6. AwaitUnsafeOnCompleted
         [DebuggerHidden]
         [SecuritySafeCritical]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void AwaitUnsafeOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine)
             where TAwaiter : ICriticalNotifyCompletion
             where TStateMachine : IAsyncStateMachine
         {
             if (runner == null)
             {
-                runner = MoveNextRunner<TStateMachine>.Create(ref stateMachine);
+                AsyncUniTaskVoid<TStateMachine>.SetStateMachine(ref this, ref stateMachine);
             }
 
-            awaiter.OnCompleted(runner.CallMoveNext);
+            awaiter.UnsafeOnCompleted(runner.MoveNext);
         }
 
         // 7. Start

src/UniTask/Assets/Plugins/UniTask/Runtime/CompilerServices/MoveNextRunner.cs

@@ -1,57 +0,0 @@
-
-#pragma warning disable CS1591 // Missing XML comment for publicly visible type or member
-
-using System;
-using System.Diagnostics;
-using System.Runtime.CompilerServices;
-using Cysharp.Threading.Tasks.Internal;
-
-namespace Cysharp.Threading.Tasks.CompilerServices
-{
-    internal interface IMoveNextRunner
-    {
-        Action CallMoveNext { get; }
-        void Return();
-    }
-
-    internal sealed class MoveNextRunner<TStateMachine> : IMoveNextRunner, IPromisePoolItem
-        where TStateMachine : IAsyncStateMachine
-    {
-        static PromisePool<MoveNextRunner<TStateMachine>> pool = new PromisePool<MoveNextRunner<TStateMachine>>();
-
-        TStateMachine stateMachine;
-        internal readonly Action callMoveNext;
-
-        public Action CallMoveNext => callMoveNext;
-
-        MoveNextRunner()
-        {
-            callMoveNext = MoveNext;
-        }
-
-        public static MoveNextRunner<TStateMachine> Create(ref TStateMachine stateMachine)
-        {
-            var result = pool.TryRent() ?? new MoveNextRunner<TStateMachine>();
-            result.stateMachine = stateMachine;
-            return result;
-        }
-
-        [DebuggerHidden]
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        void MoveNext()
-        {
-            stateMachine.MoveNext();
-        }
-
-        public void Return()
-        {
-            pool.TryReturn(this);
-        }
-
-        void IPromisePoolItem.Reset()
-        {
-            stateMachine = default;
-        }
-    }
-}
-

src/UniTask/Assets/Plugins/UniTask/Runtime/CompilerServices/StateMachineRunner.cs

@@ -0,0 +1,328 @@
+#pragma warning disable CS1591 // Missing XML comment for publicly visible type or member
+
+using Cysharp.Threading.Tasks.Internal;
+using System;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+
+namespace Cysharp.Threading.Tasks.CompilerServices
+{
+    internal interface IStateMachineRunner
+    {
+        Action MoveNext { get; }
+        void Return();
+    }
+
+    internal interface IStateMachineRunnerPromise : IUniTaskSource
+    {
+        Action MoveNext { get; }
+        UniTask Task { get; }
+        void SetResult();
+        void SetException(Exception exception);
+    }
+
+    internal interface IStateMachineRunnerPromise<T> : IUniTaskSource<T>
+    {
+        Action MoveNext { get; }
+        UniTask<T> Task { get; }
+        void SetResult(T result);
+        void SetException(Exception exception);
+    }
+
+    internal sealed class AsyncUniTaskVoid<TStateMachine> : IStateMachineRunner, ITaskPoolNode<AsyncUniTaskVoid<TStateMachine>>, IUniTaskSource
+        where TStateMachine : IAsyncStateMachine
+    {
+        static TaskPool<AsyncUniTaskVoid<TStateMachine>> pool;
+
+        TStateMachine stateMachine;
+
+        public Action MoveNext { get; }
+
+        public AsyncUniTaskVoid()
+        {
+            MoveNext = Run;
+        }
+
+        public static void SetStateMachine(ref AsyncUniTaskVoidMethodBuilder builder, ref TStateMachine stateMachine)
+        {
+            if (!pool.TryPop(out var result))
+            {
+                result = new AsyncUniTaskVoid<TStateMachine>();
+            }
+            TaskTracker.TrackActiveTask(result, 3);
+
+            builder.runner = result; // set runner before copied.
+            result.stateMachine = stateMachine; // copy struct StateMachine(in release build).
+        }
+
+        static AsyncUniTaskVoid()
+        {
+            TaskPool.RegisterSizeGetter(typeof(AsyncUniTaskVoid<TStateMachine>), () => pool.Size);
+        }
+
+        public AsyncUniTaskVoid<TStateMachine> NextNode { get; set; }
+
+        public void Return()
+        {
+            TaskTracker.RemoveTracking(this);
+            stateMachine = default;
+            pool.TryPush(this);
+        }
+
+        [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        void Run()
+        {
+            stateMachine.MoveNext();
+        }
+
+        // dummy interface implementation for TaskTracker.
+
+        UniTaskStatus IUniTaskSource.GetStatus(short token)
+        {
+            return UniTaskStatus.Pending;
+        }
+
+        UniTaskStatus IUniTaskSource.UnsafeGetStatus()
+        {
+            return UniTaskStatus.Pending;
+        }
+
+        void IUniTaskSource.OnCompleted(Action<object> continuation, object state, short token)
+        {
+        }
+
+        void IUniTaskSource.GetResult(short token)
+        {
+        }
+    }
+
+    internal sealed class AsyncUniTask<TStateMachine> : IStateMachineRunnerPromise, IUniTaskSource, ITaskPoolNode<AsyncUniTask<TStateMachine>>
+        where TStateMachine : IAsyncStateMachine
+    {
+        static TaskPool<AsyncUniTask<TStateMachine>> pool;
+
+        TStateMachine stateMachine;
+
+        public Action MoveNext { get; }
+
+        UniTaskCompletionSourceCore<AsyncUnit> core;
+
+        AsyncUniTask()
+        {
+            MoveNext = Run;
+        }
+
+        public static void SetStateMachine(ref AsyncUniTaskMethodBuilder builder, ref TStateMachine stateMachine)
+        {
+            if (!pool.TryPop(out var result))
+            {
+                result = new AsyncUniTask<TStateMachine>();
+            }
+            TaskTracker.TrackActiveTask(result, 3);
+
+            builder.runnerPromise = result; // set runner before copied.
+            result.stateMachine = stateMachine; // copy struct StateMachine(in release build).
+        }
+
+        public AsyncUniTask<TStateMachine> NextNode { get; set; }
+
+        static AsyncUniTask()
+        {
+            TaskPool.RegisterSizeGetter(typeof(AsyncUniTask<TStateMachine>), () => pool.Size);
+        }
+
+        bool TryReturn()
+        {
+            TaskTracker.RemoveTracking(this);
+            core.Reset();
+            stateMachine = default;
+            return pool.TryPush(this);
+        }
+
+        [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        void Run()
+        {
+            stateMachine.MoveNext();
+        }
+
+        public UniTask Task
+        {
+            [DebuggerHidden]
+            get
+            {
+                return new UniTask(this, core.Version);
+            }
+        }
+
+        [DebuggerHidden]
+        public void SetResult()
+        {
+            core.TrySetResult(AsyncUnit.Default);
+        }
+
+        [DebuggerHidden]
+        public void SetException(Exception exception)
+        {
+            core.TrySetException(exception);
+        }
+
+        [DebuggerHidden]
+        public void GetResult(short token)
+        {
+            try
+            {
+                core.GetResult(token);
+            }
+            finally
+            {
+                TryReturn();
+            }
+        }
+
+        [DebuggerHidden]
+        public UniTaskStatus GetStatus(short token)
+        {
+            return core.GetStatus(token);
+        }
+
+        [DebuggerHidden]
+        public UniTaskStatus UnsafeGetStatus()
+        {
+            return core.UnsafeGetStatus();
+        }
+
+        [DebuggerHidden]
+        public void OnCompleted(Action<object> continuation, object state, short token)
+        {
+            core.OnCompleted(continuation, state, token);
+        }
+
+        ~AsyncUniTask()
+        {
+            if (TryReturn())
+            {
+                GC.ReRegisterForFinalize(this);
+            }
+        }
+    }
+
+    internal sealed class AsyncUniTask<TStateMachine, T> : IStateMachineRunnerPromise<T>, IUniTaskSource<T>, ITaskPoolNode<AsyncUniTask<TStateMachine, T>>
+        where TStateMachine : IAsyncStateMachine
+    {
+        static TaskPool<AsyncUniTask<TStateMachine, T>> pool;
+
+        TStateMachine stateMachine;
+
+        public Action MoveNext { get; }
+
+        UniTaskCompletionSourceCore<T> core;
+
+        AsyncUniTask()
+        {
+            MoveNext = Run;
+        }
+
+        public static void SetStateMachine(ref AsyncUniTaskMethodBuilder<T> builder, ref TStateMachine stateMachine)
+        {
+            if (!pool.TryPop(out var result))
+            {
+                result = new AsyncUniTask<TStateMachine, T>();
+            }
+            TaskTracker.TrackActiveTask(result, 3);
+
+            builder.runnerPromise = result; // set runner before copied.
+            result.stateMachine = stateMachine; // copy struct StateMachine(in release build).
+        }
+
+        public AsyncUniTask<TStateMachine, T> NextNode { get; set; }
+
+        static AsyncUniTask()
+        {
+            TaskPool.RegisterSizeGetter(typeof(AsyncUniTask<TStateMachine, T>), () => pool.Size);
+        }
+
+        bool TryReturn()
+        {
+            TaskTracker.RemoveTracking(this);
+            core.Reset();
+            stateMachine = default;
+            return pool.TryPush(this);
+        }
+
+        [DebuggerHidden]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        void Run()
+        {
+            stateMachine.MoveNext();
+        }
+
+        public UniTask<T> Task
+        {
+            [DebuggerHidden]
+            get
+            {
+                return new UniTask<T>(this, core.Version);
+            }
+        }
+
+        [DebuggerHidden]
+        public void SetResult(T result)
+        {
+            core.TrySetResult(result);
+        }
+
+        [DebuggerHidden]
+        public void SetException(Exception exception)
+        {
+            core.TrySetException(exception);
+        }
+
+        [DebuggerHidden]
+        public T GetResult(short token)
+        {
+            try
+            {
+                return core.GetResult(token);
+            }
+            finally
+            {
+                TryReturn();
+            }
+        }
+
+        [DebuggerHidden]
+        void IUniTaskSource.GetResult(short token)
+        {
+            GetResult(token);
+        }
+
+        [DebuggerHidden]
+        public UniTaskStatus GetStatus(short token)
+        {
+            return core.GetStatus(token);
+        }
+
+        [DebuggerHidden]
+        public UniTaskStatus UnsafeGetStatus()
+        {
+            return core.UnsafeGetStatus();
+        }
+
+        [DebuggerHidden]
+        public void OnCompleted(Action<object> continuation, object state, short token)
+        {
+            core.OnCompleted(continuation, state, token);
+        }
+
+        ~AsyncUniTask()
+        {
+            if (TryReturn())
+            {
+                GC.ReRegisterForFinalize(this);
+            }
+        }
+    }
+}
+

src/UniTask/Assets/Plugins/UniTask/Runtime/EnumeratorAsyncExtensions.cs

@@ -12,10 +12,12 @@ namespace Cysharp.Threading.Tasks
 {
     public static class EnumeratorAsyncExtensions
     {
-        public static UniTask.Awaiter GetAwaiter(this IEnumerator enumerator)
+        public static UniTask.Awaiter GetAwaiter<T>(this T enumerator)
+            where T : IEnumerator
         {
-            Error.ThrowArgumentNullException(enumerator, nameof(enumerator));
-            return new UniTask(EnumeratorPromise.Create(enumerator, PlayerLoopTiming.Update, CancellationToken.None, out var token), token).GetAwaiter();
+            var e = (IEnumerator)enumerator;
+            Error.ThrowArgumentNullException(e, nameof(enumerator));
+            return new UniTask(EnumeratorPromise.Create(e, PlayerLoopTiming.Update, CancellationToken.None, out var token), token).GetAwaiter();
         }
 
         public static UniTask WithCancellation(this IEnumerator enumerator, CancellationToken cancellationToken)
@@ -30,9 +32,15 @@ namespace Cysharp.Threading.Tasks
             return new UniTask(EnumeratorPromise.Create(enumerator, timing, cancellationToken, out var token), token);
         }
 
-        class EnumeratorPromise : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        sealed class EnumeratorPromise : IUniTaskSource, IPlayerLoopItem, ITaskPoolNode<EnumeratorPromise>
         {
-            static readonly PromisePool<EnumeratorPromise> pool = new PromisePool<EnumeratorPromise>();
+            static TaskPool<EnumeratorPromise> pool;
+            public EnumeratorPromise NextNode { get; set; }
+
+            static EnumeratorPromise()
+            {
+                TaskPool.RegisterSizeGetter(typeof(EnumeratorPromise), () => pool.Size);
+            }
 
             IEnumerator innerEnumerator;
             CancellationToken cancellationToken;
@@ -50,13 +58,15 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new EnumeratorPromise();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new EnumeratorPromise();
+                }
+                TaskTracker.TrackActiveTask(result, 3);
 
                 result.innerEnumerator = ConsumeEnumerator(innerEnumerator);
                 result.cancellationToken = cancellationToken;
 
-                TaskTracker.TrackActiveTask(result, 3);
-
                 PlayerLoopHelper.AddAction(timing, result);
 
                 token = result.core.Version;
@@ -67,12 +77,11 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
                     core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -116,16 +125,18 @@ namespace Cysharp.Threading.Tasks
                 return false;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
                 innerEnumerator = default;
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~EnumeratorPromise()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }

src/UniTask/Assets/Plugins/UniTask/Runtime/External/AddressableAsyncExtensions.cs

@@ -72,14 +72,20 @@ namespace Cysharp.Threading.Tasks
             public void UnsafeOnCompleted(Action continuation)
             {
                 Error.ThrowWhenContinuationIsAlreadyRegistered(continuationAction);
-                continuationAction = continuation.AsFuncOfT<AsyncOperationHandle>(); // allocate delegate.
+                continuationAction = PooledDelegate<AsyncOperationHandle>.Create(continuation);
                 handle.Completed += continuationAction;
             }
         }
 
-        sealed class AsyncOperationHandleConfiguredSource : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        sealed class AsyncOperationHandleConfiguredSource : IUniTaskSource, IPlayerLoopItem, ITaskPoolNode<AsyncOperationHandleConfiguredSource>
         {
-            static readonly PromisePool<AsyncOperationHandleConfiguredSource> pool = new PromisePool<AsyncOperationHandleConfiguredSource>();
+            static TaskPool<AsyncOperationHandleConfiguredSource> pool;
+            public AsyncOperationHandleConfiguredSource NextNode { get; set; }
+
+            static AsyncOperationHandleConfiguredSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(AsyncOperationHandleConfiguredSource), () => pool.Size);
+            }
 
             AsyncOperationHandle handle;
             IProgress<float> progress;
@@ -99,7 +105,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new AsyncOperationHandleConfiguredSource();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new AsyncOperationHandleConfiguredSource();
+                }
 
                 result.handle = handle;
                 result.progress = progress;
@@ -117,12 +126,12 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
+
                     core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -170,17 +179,19 @@ namespace Cysharp.Threading.Tasks
                 return true;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
                 core.Reset();
+                TaskTracker.RemoveTracking(this);
                 handle = default;
                 progress = default;
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~AsyncOperationHandleConfiguredSource()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
@@ -202,10 +213,10 @@ namespace Cysharp.Threading.Tasks
             return new UniTask<T>(AsyncOperationHandleConfiguredSource<T>.Create(handle, PlayerLoopTiming.Update, null, cancellationToken, out var token), token);
         }
 
-        public static UniTask<T> ToUniTask<T>(this AsyncOperationHandle<T> handle, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellation = default(CancellationToken))
+        public static UniTask<T> ToUniTask<T>(this AsyncOperationHandle<T> handle, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken))
         {
             if (handle.IsDone) return UniTask.FromResult(handle.Result);
-            return new UniTask<T>(AsyncOperationHandleConfiguredSource<T>.Create(handle, timing, progress, cancellation, out var token), token);
+            return new UniTask<T>(AsyncOperationHandleConfiguredSource<T>.Create(handle, timing, progress, cancellationToken, out var token), token);
         }
 
         public struct AsyncOperationHandleAwaiter<T> : ICriticalNotifyCompletion
@@ -249,14 +260,20 @@ namespace Cysharp.Threading.Tasks
             public void UnsafeOnCompleted(Action continuation)
             {
                 Error.ThrowWhenContinuationIsAlreadyRegistered(continuationAction);
-                continuationAction = continuation.AsFuncOfT<AsyncOperationHandle>(); // allocate delegate.
+                continuationAction = PooledDelegate<AsyncOperationHandle>.Create(continuation);
                 handle.CompletedTypeless += continuationAction;
             }
         }
 
-        sealed class AsyncOperationHandleConfiguredSource<T> : IUniTaskSource<T>, IPlayerLoopItem, IPromisePoolItem
+        sealed class AsyncOperationHandleConfiguredSource<T> : IUniTaskSource<T>, IPlayerLoopItem, ITaskPoolNode<AsyncOperationHandleConfiguredSource<T>>
         {
-            static readonly PromisePool<AsyncOperationHandleConfiguredSource<T>> pool = new PromisePool<AsyncOperationHandleConfiguredSource<T>>();
+            static TaskPool<AsyncOperationHandleConfiguredSource<T>> pool;
+            public AsyncOperationHandleConfiguredSource<T> NextNode { get; set; }
+
+            static AsyncOperationHandleConfiguredSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(AsyncOperationHandleConfiguredSource<T>), () => pool.Size);
+            }
 
             AsyncOperationHandle<T> handle;
             IProgress<float> progress;
@@ -276,7 +293,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource<T>.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new AsyncOperationHandleConfiguredSource<T>();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new AsyncOperationHandleConfiguredSource<T>();
+                }
 
                 result.handle = handle;
                 result.progress = progress;
@@ -294,13 +314,11 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
-
                     return core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -353,17 +371,19 @@ namespace Cysharp.Threading.Tasks
                 return true;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
                 handle = default;
                 progress = default;
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~AsyncOperationHandleConfiguredSource()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }

src/UniTask/Assets/Plugins/UniTask/Runtime/External/DoTweenAsyncExtensions.cs

@@ -5,6 +5,7 @@
 using Cysharp.Threading.Tasks.Internal;
 using DG.Tweening;
 using System;
+using System.Collections.Concurrent;
 using System.Runtime.CompilerServices;
 using System.Threading;
 
@@ -33,7 +34,7 @@ namespace Cysharp.Threading.Tasks
             return new TweenAwaiter(tween);
         }
 
-        public static UniTask WithCancellation(this Tween tween, CancellationToken cancellationToken = default)
+        public static UniTask WithCancellation(this Tween tween, CancellationToken cancellationToken)
         {
             Error.ThrowArgumentNullException(tween, nameof(tween));
 
@@ -77,75 +78,79 @@ namespace Cysharp.Threading.Tasks
 
             public void UnsafeOnCompleted(System.Action continuation)
             {
-                // convert Action -> TweenCallback allocation.
                 // onKill is called after OnCompleted, both Complete(false/true) and Kill(false/true).
-                tween.onKill = new TweenCallback(continuation);
+                tween.onKill = PooledTweenCallback.Create(continuation);
             }
         }
 
-        sealed class TweenConfiguredSource : IUniTaskSource, IPromisePoolItem
+        sealed class TweenConfiguredSource : IUniTaskSource, ITaskPoolNode<TweenConfiguredSource>
         {
-            static readonly PromisePool<TweenConfiguredSource> pool = new PromisePool<TweenConfiguredSource>();
-            static Action<object> CancellationCallbackDelegate = CancellationCallback;
+            static TaskPool<TweenConfiguredSource> pool;
+            public TweenConfiguredSource NextNode { get; set; }
+
+            static TweenConfiguredSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(TweenConfiguredSource), () => pool.Size);
+            }
+
+            static readonly TweenCallback EmptyTweenCallback = () => { };
+
+            readonly TweenCallback onKillDelegate;
+            readonly TweenCallback onUpdateDelegate;
 
             Tween tween;
             TweenCancelBehaviour cancelBehaviour;
             CancellationToken cancellationToken;
             bool canceled;
 
-            CancellationTokenRegistration cancellationTokenRegistration;
+            TweenCallback originalUpdateAction;
             UniTaskCompletionSourceCore<AsyncUnit> core;
 
             TweenConfiguredSource()
             {
-
+                onKillDelegate = OnKill;
+                onUpdateDelegate = OnUpdate;
             }
 
             public static IUniTaskSource Create(Tween tween, TweenCancelBehaviour cancelBehaviour, CancellationToken cancellationToken, out short token)
             {
                 if (cancellationToken.IsCancellationRequested)
                 {
+                    DoCancelBeforeCreate(tween, cancelBehaviour);
                     return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new TweenConfiguredSource();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new TweenConfiguredSource();
+                }
 
                 result.tween = tween;
                 result.cancelBehaviour = cancelBehaviour;
                 result.cancellationToken = cancellationToken;
 
-                TaskTracker.TrackActiveTask(result, 3);
+                result.originalUpdateAction = tween.onUpdate;
+                result.canceled = false;
 
-                result.RegisterEvent();
+                if (result.originalUpdateAction == result.onUpdateDelegate)
+                {
+                    result.originalUpdateAction = null;
+                }
+
+                tween.onUpdate = result.onUpdateDelegate;
+                tween.onKill = result.onKillDelegate;
+
+                TaskTracker.TrackActiveTask(result, 3);
 
                 token = result.core.Version;
                 return result;
             }
 
-            void RegisterEvent()
-            {
-                if (cancellationToken.CanBeCanceled)
-                {
-                    cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(CancellationCallbackDelegate, this);
-                }
-
-                // allocate delegate.
-                tween.OnKill(new TweenCallback(OnKill));
-            }
-
             void OnKill()
             {
-                cancellationTokenRegistration.Dispose();
                 if (canceled)
                 {
-                    if (cancelBehaviour == TweenCancelBehaviour.CancelAwait)
-                    {
-                        // already called TrySetCanceled, do nothing.
-                    }
-                    else
-                    {
-                        core.TrySetCanceled(cancellationToken);
-                    }
+                    core.TrySetCanceled(cancellationToken);
                 }
                 else
                 {
@@ -153,44 +158,84 @@ namespace Cysharp.Threading.Tasks
                 }
             }
 
-            static void CancellationCallback(object state)
+            void OnUpdate()
             {
-                var self = (TweenConfiguredSource)state;
+                originalUpdateAction?.Invoke();
 
-                switch (self.cancelBehaviour)
+                if (!cancellationToken.IsCancellationRequested)
+                {
+                    return;
+                }
+
+                switch (this.cancelBehaviour)
                 {
                     case TweenCancelBehaviour.Kill:
                     default:
-                        self.tween.Kill(false);
+                        this.tween.Kill(false);
                         break;
                     case TweenCancelBehaviour.KillAndCancelAwait:
-                        self.canceled = true;
-                        self.tween.Kill(false);
+                        this.canceled = true;
+                        this.tween.Kill(false);
                         break;
                     case TweenCancelBehaviour.KillWithCompleteCallback:
-                        self.tween.Kill(true);
+                        this.tween.Kill(true);
                         break;
                     case TweenCancelBehaviour.KillWithCompleteCallbackAndCancelAwait:
-                        self.canceled = true;
-                        self.tween.Kill(true);
+                        this.canceled = true;
+                        this.tween.Kill(true);
                         break;
                     case TweenCancelBehaviour.Complete:
-                        self.tween.Complete(false);
+                        this.tween.Complete(false);
                         break;
                     case TweenCancelBehaviour.CompleteAndCancelAwait:
-                        self.canceled = true;
-                        self.tween.Complete(false);
+                        this.canceled = true;
+                        this.tween.Complete(false);
                         break;
                     case TweenCancelBehaviour.CompleteWithSeqeunceCallback:
-                        self.tween.Complete(true);
+                        this.tween.Complete(true);
                         break;
                     case TweenCancelBehaviour.CompleteWithSeqeunceCallbackAndCancelAwait:
-                        self.canceled = true;
-                        self.tween.Complete(true);
+                        this.canceled = true;
+                        this.tween.Complete(true);
+                        break;
+                    case TweenCancelBehaviour.CancelAwait:
+                        this.tween.onKill = EmptyTweenCallback; // replace to empty(avoid callback after Canceled(instance is returned to pool.)
+                        this.core.TrySetCanceled(this.cancellationToken);
+                        break;
+                }
+            }
+
+            static void DoCancelBeforeCreate(Tween tween, TweenCancelBehaviour tweenCancelBehaviour)
+            {
+
+                switch (tweenCancelBehaviour)
+                {
+                    case TweenCancelBehaviour.Kill:
+                    default:
+                        tween.Kill(false);
+                        break;
+                    case TweenCancelBehaviour.KillAndCancelAwait:
+                        tween.Kill(false);
+                        break;
+                    case TweenCancelBehaviour.KillWithCompleteCallback:
+                        tween.Kill(true);
+                        break;
+                    case TweenCancelBehaviour.KillWithCompleteCallbackAndCancelAwait:
+                        tween.Kill(true);
+                        break;
+                    case TweenCancelBehaviour.Complete:
+                        tween.Complete(false);
+                        break;
+                    case TweenCancelBehaviour.CompleteAndCancelAwait:
+                        tween.Complete(false);
+                        break;
+                    case TweenCancelBehaviour.CompleteWithSeqeunceCallback:
+                        tween.Complete(true);
+                        break;
+                    case TweenCancelBehaviour.CompleteWithSeqeunceCallbackAndCancelAwait:
+                        tween.Complete(true);
                         break;
                     case TweenCancelBehaviour.CancelAwait:
-                        self.canceled = true;
-                        self.core.TrySetCanceled(self.cancellationToken);
                         break;
                 }
             }
@@ -199,16 +244,14 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
                     core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
-
             public UniTaskStatus GetStatus(short token)
             {
                 return core.GetStatus(token);
@@ -224,22 +267,66 @@ namespace Cysharp.Threading.Tasks
                 core.OnCompleted(continuation, state, token);
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
+                tween.onUpdate = originalUpdateAction;
+                tween.onKill = null;
                 tween = default;
                 cancellationToken = default;
+                originalUpdateAction = default;
+                return pool.TryPush(this);
             }
 
             ~TweenConfiguredSource()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
             }
         }
     }
+
+    sealed class PooledTweenCallback
+    {
+        static readonly ConcurrentQueue<PooledTweenCallback> pool = new ConcurrentQueue<PooledTweenCallback>();
+
+        readonly TweenCallback runDelegate;
+
+        Action continuation;
+
+
+        PooledTweenCallback()
+        {
+            runDelegate = Run;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static TweenCallback Create(Action continuation)
+        {
+            if (!pool.TryDequeue(out var item))
+            {
+                item = new PooledTweenCallback();
+            }
+
+            item.continuation = continuation;
+            return item.runDelegate;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        void Run()
+        {
+            var call = continuation;
+            continuation = null;
+            if (call != null)
+            {
+                pool.Enqueue(this);
+                call.Invoke();
+            }
+        }
+    }
 }
 
 #endif

src/UniTask/Assets/Plugins/UniTask/Runtime/IUniTaskSource.cs

@@ -19,17 +19,75 @@ namespace Cysharp.Threading.Tasks
 
     // similar as IValueTaskSource
     public interface IUniTaskSource
+#if !UNITY_2018_3_OR_NEWER && !NETSTANDARD2_0
+        : System.Threading.Tasks.Sources.IValueTaskSource
+#pragma warning disable CS0108
+#endif
     {
         UniTaskStatus GetStatus(short token);
         void OnCompleted(Action<object> continuation, object state, short token);
         void GetResult(short token);
 
         UniTaskStatus UnsafeGetStatus(); // only for debug use.
+
+#if !UNITY_2018_3_OR_NEWER && !NETSTANDARD2_0
+#pragma warning restore CS0108
+
+        System.Threading.Tasks.Sources.ValueTaskSourceStatus System.Threading.Tasks.Sources.IValueTaskSource.GetStatus(short token)
+        {
+            return (System.Threading.Tasks.Sources.ValueTaskSourceStatus)(int)((IUniTaskSource)this).GetStatus(token);
+        }
+
+        void System.Threading.Tasks.Sources.IValueTaskSource.GetResult(short token)
+        {
+            ((IUniTaskSource)this).GetResult(token);
+        }
+
+        void System.Threading.Tasks.Sources.IValueTaskSource.OnCompleted(Action<object> continuation, object state, short token, System.Threading.Tasks.Sources.ValueTaskSourceOnCompletedFlags flags)
+        {
+            // ignore flags, always none.
+            ((IUniTaskSource)this).OnCompleted(continuation, state, token);
+        }
+
+#endif
     }
 
     public interface IUniTaskSource<out T> : IUniTaskSource
+#if !UNITY_2018_3_OR_NEWER && !NETSTANDARD2_0
+        , System.Threading.Tasks.Sources.IValueTaskSource<T>
+#endif
     {
         new T GetResult(short token);
+
+#if !UNITY_2018_3_OR_NEWER && !NETSTANDARD2_0
+
+        new public UniTaskStatus GetStatus(short token)
+        {
+            return ((IUniTaskSource)this).GetStatus(token);
+        }
+
+        new public void OnCompleted(Action<object> continuation, object state, short token)
+        {
+            ((IUniTaskSource)this).OnCompleted(continuation, state, token);
+        }
+
+        System.Threading.Tasks.Sources.ValueTaskSourceStatus System.Threading.Tasks.Sources.IValueTaskSource<T>.GetStatus(short token)
+        {
+            return (System.Threading.Tasks.Sources.ValueTaskSourceStatus)(int)((IUniTaskSource)this).GetStatus(token);
+        }
+
+        T System.Threading.Tasks.Sources.IValueTaskSource<T>.GetResult(short token)
+        {
+            return ((IUniTaskSource<T>)this).GetResult(token);
+        }
+
+        void System.Threading.Tasks.Sources.IValueTaskSource<T>.OnCompleted(Action<object> continuation, object state, short token, System.Threading.Tasks.Sources.ValueTaskSourceOnCompletedFlags flags)
+        {
+            // ignore flags, always none.
+            ((IUniTaskSource)this).OnCompleted(continuation, state, token);
+        }
+
+#endif
     }
 
     public static class UniTaskStatusExtensions

src/UniTask/Assets/Plugins/UniTask/Runtime/Internal/Hack.cs

@@ -1,23 +0,0 @@
-#if NET_4_6 || NET_STANDARD_2_0 || CSHARP_7_OR_LATER
-
-using System;
-
-namespace Cysharp.Threading.Tasks.Internal
-{
-    internal static class FuncExtensions
-    {
-        // avoid lambda capture
-
-        internal static Action<T> AsFuncOfT<T>(this Action action)
-        {
-            return new Action<T>(action.Invoke);
-        }
-
-        static void Invoke<T>(this Action action, T unused)
-        {
-            action();
-        }
-    }
-}
-
-#endif

src/UniTask/Assets/Plugins/UniTask/Runtime/Internal/PooledDelegate.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Runtime.CompilerServices;
+
+namespace Cysharp.Threading.Tasks.Internal
+{
+    internal sealed class PooledDelegate<T> : ITaskPoolNode<PooledDelegate<T>>
+    {
+        static TaskPool<PooledDelegate<T>> pool;
+
+        public PooledDelegate<T> NextNode { get; set; }
+
+        static PooledDelegate()
+        {
+            TaskPool.RegisterSizeGetter(typeof(PooledDelegate<T>), () => pool.Size);
+        }
+
+        readonly Action<T> runDelegate;
+        Action continuation;
+
+        PooledDelegate()
+        {
+            runDelegate = Run;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static Action<T> Create(Action continuation)
+        {
+            if (!pool.TryPop(out var item))
+            {
+                item = new PooledDelegate<T>();
+            }
+
+            item.continuation = continuation;
+            return item.runDelegate;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        void Run(T _)
+        {
+            var call = continuation;
+            continuation = null;
+            if (call != null)
+            {
+                pool.TryPush(this);
+                call.Invoke();
+            }
+        }
+    }
+}

src/UniTask/Assets/Plugins/UniTask/Runtime/Internal/PooledDelegate.cs.meta

@@ -1,5 +1,5 @@
 fileFormatVersion: 2
-guid: 4d5a9a3e1f0f069478969f752fde29a9
+guid: 8932579438742fa40b010edd412dbfba
 MonoImporter:
   externalObjects: {}
   serializedVersion: 2

src/UniTask/Assets/Plugins/UniTask/Runtime/Internal/PromisePool.cs

@@ -1,55 +0,0 @@
-using System.Collections.Concurrent;
-using System.Runtime.CompilerServices;
-using System.Threading;
-
-namespace Cysharp.Threading.Tasks.Internal
-{
-    // public, allow to user create custom operator with pool.
-
-    public interface IPromisePoolItem
-    {
-        void Reset();
-    }
-
-    public class PromisePool<T>
-        where T : class, IPromisePoolItem
-    {
-        int count = 0;
-        readonly ConcurrentQueue<T> queue = new ConcurrentQueue<T>();
-        readonly int maxSize;
-
-        public PromisePool(int maxSize = 256)
-        {
-            this.maxSize = maxSize;
-        }
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public T TryRent()
-        {
-            if (queue.TryDequeue(out var value))
-            {
-                Interlocked.Decrement(ref count);
-                return value;
-            }
-
-            return null;
-        }
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool TryReturn(T value)
-        {
-            value.Reset(); // reset when return.
-
-            if (count < maxSize)
-            {
-                queue.Enqueue(value);
-                Interlocked.Increment(ref count);
-                return true;
-            }
-            else
-            {
-                return false;
-            }
-        }
-    }
-}

src/UniTask/Assets/Plugins/UniTask/Runtime/Internal/TaskTracker.cs

@@ -3,6 +3,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Text;
 using System.Threading;
 using Cysharp.Threading.Tasks.Internal;
 
@@ -59,9 +60,9 @@ namespace Cysharp.Threading.Tasks
 #endif
 
 
-        static List<KeyValuePair<IUniTaskSource, (int trackingId, DateTime addTime, string stackTrace)>> listPool = new List<KeyValuePair<IUniTaskSource, (int trackingId, DateTime addTime, string stackTrace)>>();
+        static List<KeyValuePair<IUniTaskSource, (string formattedType, int trackingId, DateTime addTime, string stackTrace)>> listPool = new List<KeyValuePair<IUniTaskSource, (string formattedType, int trackingId, DateTime addTime, string stackTrace)>>();
 
-        static readonly WeakDictionary<IUniTaskSource, (int trackingId, DateTime addTime, string stackTrace)> tracking = new WeakDictionary<IUniTaskSource, (int trackingId, DateTime addTime, string stackTrace)>();
+        static readonly WeakDictionary<IUniTaskSource, (string formattedType, int trackingId, DateTime addTime, string stackTrace)> tracking = new WeakDictionary<IUniTaskSource, (string formattedType, int trackingId, DateTime addTime, string stackTrace)>();
 
         [Conditional("UNITY_EDITOR")]
         public static void TrackActiveTask(IUniTaskSource task, int skipFrame)
@@ -70,7 +71,19 @@ namespace Cysharp.Threading.Tasks
             dirty = true;
             if (!EditorEnableState.EnableTracking) return;
             var stackTrace = EditorEnableState.EnableStackTrace ? new StackTrace(skipFrame, true).CleanupAsyncStackTrace() : "";
-            tracking.TryAdd(task, (Interlocked.Increment(ref trackingId), DateTime.UtcNow, stackTrace));
+
+            string typeName;
+            if (EditorEnableState.EnableStackTrace)
+            {
+                var sb = new StringBuilder();
+                TypeBeautify(task.GetType(), sb);
+                typeName = sb.ToString();
+            }
+            else
+            {
+                typeName = task.GetType().Name;
+            }
+            tracking.TryAdd(task, (typeName, Interlocked.Increment(ref trackingId), DateTime.UtcNow, stackTrace));
 #endif
         }
 
@@ -103,19 +116,8 @@ namespace Cysharp.Threading.Tasks
                 {
                     for (int i = 0; i < count; i++)
                     {
-                        string typeName = null;
-                        var keyType = listPool[i].Key.GetType();
-                        if (keyType.IsNested)
-                        {
-                            typeName = keyType.DeclaringType.Name + "." + keyType.Name;
-                        }
-                        else
-                        {
-                            typeName = keyType.Name;
-                        }
-
-                        action(listPool[i].Value.trackingId, typeName, listPool[i].Key.UnsafeGetStatus(), listPool[i].Value.addTime, listPool[i].Value.stackTrace);
-                        listPool[i] = new KeyValuePair<IUniTaskSource, (int trackingId, DateTime addTime, string stackTrace)>(null, (0, default(DateTime), null)); // clear
+                        action(listPool[i].Value.trackingId, listPool[i].Value.formattedType, listPool[i].Key.UnsafeGetStatus(), listPool[i].Value.addTime, listPool[i].Value.stackTrace);
+                        listPool[i] = default;
                     }
                 }
                 catch
@@ -125,6 +127,52 @@ namespace Cysharp.Threading.Tasks
                 }
             }
         }
+
+        static void TypeBeautify(Type type, StringBuilder sb)
+        {
+            if (type.IsNested)
+            {
+                // TypeBeautify(type.DeclaringType, sb);
+                sb.Append(type.DeclaringType.Name.ToString());
+                sb.Append(".");
+            }
+
+            if (type.IsGenericType)
+            {
+                var genericsStart = type.Name.IndexOf("`");
+                if (genericsStart != -1)
+                {
+                    sb.Append(type.Name.Substring(0, genericsStart));
+                }
+                else
+                {
+                    sb.Append(type.Name);
+                }
+                sb.Append("<");
+                var first = true;
+                foreach (var item in type.GetGenericArguments())
+                {
+                    if (!first)
+                    {
+                        sb.Append(", ");
+                    }
+                    first = false;
+                    TypeBeautify(item, sb);
+                }
+                sb.Append(">");
+            }
+            else
+            {
+                sb.Append(type.Name);
+            }
+        }
+
+        //static string RemoveUniTaskNamespace(string str)
+        //{
+        //    return str.Replace("Cysharp.Threading.Tasks.CompilerServices", "")
+        //        .Replace("Cysharp.Threading.Tasks.Linq", "")
+        //        .Replace("Cysharp.Threading.Tasks", "");
+        //}
     }
 }
 

src/UniTask/Assets/Plugins/UniTask/Runtime/Linq/AsyncEnumeratorBase.cs

@@ -3,66 +3,9 @@ using System.Threading;
 
 namespace Cysharp.Threading.Tasks.Linq
 {
-    public abstract class MoveNextSource : IUniTaskSource<bool>
-    {
-        protected UniTaskCompletionSourceCore<bool> completionSource;
-
-        public bool GetResult(short token)
-        {
-            return completionSource.GetResult(token);
-        }
-
-        public UniTaskStatus GetStatus(short token)
-        {
-            return completionSource.GetStatus(token);
-        }
-
-        public void OnCompleted(Action<object> continuation, object state, short token)
-        {
-            completionSource.OnCompleted(continuation, state, token);
-        }
-
-        public UniTaskStatus UnsafeGetStatus()
-        {
-            return completionSource.UnsafeGetStatus();
-        }
-
-        void IUniTaskSource.GetResult(short token)
-        {
-            completionSource.GetResult(token);
-        }
-
-        protected bool TryGetResult<T>(UniTask<T>.Awaiter awaiter, out T result)
-        {
-            try
-            {
-                result = awaiter.GetResult();
-                return true;
-            }
-            catch (Exception ex)
-            {
-                completionSource.TrySetException(ex);
-                result = default;
-                return false;
-            }
-        }
-
-        protected bool TryGetResult(UniTask.Awaiter awaiter)
-        {
-            try
-            {
-                awaiter.GetResult();
-                return true;
-            }
-            catch (Exception ex)
-            {
-                completionSource.TrySetException(ex);
-                return false;
-            }
-        }
-    }
-
-    public abstract class AsyncEnumeratorBase<TSource, TResult> : MoveNextSource, IUniTaskAsyncEnumerator<TResult>
+    // note: refactor all inherit class and should remove this.
+    // see Select and Where.
+    internal abstract class AsyncEnumeratorBase<TSource, TResult> : MoveNextSource, IUniTaskAsyncEnumerator<TResult>
     {
         static readonly Action<object> moveNextCallbackDelegate = MoveNextCallBack;
 
@@ -188,7 +131,7 @@ namespace Cysharp.Threading.Tasks.Linq
         }
     }
 
-    public abstract class AsyncEnumeratorAwaitSelectorBase<TSource, TResult, TAwait> : MoveNextSource, IUniTaskAsyncEnumerator<TResult>
+    internal abstract class AsyncEnumeratorAwaitSelectorBase<TSource, TResult, TAwait> : MoveNextSource, IUniTaskAsyncEnumerator<TResult>
     {
         static readonly Action<object> moveNextCallbackDelegate = MoveNextCallBack;
         static readonly Action<object> setCurrentCallbackDelegate = SetCurrentCallBack;
@@ -410,5 +353,4 @@ namespace Cysharp.Threading.Tasks.Linq
             return default;
         }
     }
-
 }

src/UniTask/Assets/Plugins/UniTask/Runtime/Linq/DistinctUntilChanged.cs

@@ -79,41 +79,123 @@ namespace Cysharp.Threading.Tasks.Linq
             return new _DistinctUntilChanged(source, comparer, cancellationToken);
         }
 
-        class _DistinctUntilChanged : AsyncEnumeratorBase<TSource, TSource>
+        sealed class _DistinctUntilChanged : MoveNextSource, IUniTaskAsyncEnumerator<TSource>
         {
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly IEqualityComparer<TSource> comparer;
-            TSource prev;
-            bool first;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            Action moveNextAction;
 
             public _DistinctUntilChanged(IUniTaskAsyncEnumerable<TSource> source, IEqualityComparer<TSource> comparer, CancellationToken cancellationToken)
-
-                : base(source, cancellationToken)
             {
+                this.source = source;
                 this.comparer = comparer;
-                this.first = true;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override bool TryMoveNextCore(bool sourceHasCurrent, out bool result)
+            public TSource Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                if (sourceHasCurrent)
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
+            }
+
+            void MoveNext()
+            {
+                REPEAT:
+                try
                 {
-                    var v = SourceCurrent;
-                    if (first || !comparer.Equals(prev, v))
+                    switch (state)
                     {
-                        first = false;
-                        Current = prev = v;
-                        result = true;
-                        return true;
-                    }
-                    else
-                    {
-                        result = default;
-                        return false;
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case -3;
+                            }
+                            else
+                            {
+                                state = -3;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case -3: // first
+                            if (awaiter.GetResult())
+                            {
+                                Current = enumerator.Current;
+                                goto CONTINUE;
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 0: // normal
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                var v = enumerator.Current;
+                                if (!comparer.Equals(Current, v))
+                                {
+                                    Current = v;
+                                    goto CONTINUE;
+                                }
+                                else
+                                {
+                                    state = 0;
+                                    goto REPEAT;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case -2:
+                        default:
+                            goto DONE;
                     }
                 }
+                catch (Exception ex)
+                {
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
+                }
 
-                result = false;
-                return true;
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
@@ -136,45 +218,128 @@ namespace Cysharp.Threading.Tasks.Linq
             return new _DistinctUntilChanged(source, keySelector, comparer, cancellationToken);
         }
 
-        class _DistinctUntilChanged : AsyncEnumeratorBase<TSource, TSource>
+        sealed class _DistinctUntilChanged : MoveNextSource, IUniTaskAsyncEnumerator<TSource>
         {
-            readonly IEqualityComparer<TKey> comparer;
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, TKey> keySelector;
+            readonly IEqualityComparer<TKey> comparer;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            Action moveNextAction;
             TKey prev;
-            bool first;
 
             public _DistinctUntilChanged(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer, CancellationToken cancellationToken)
-
-                : base(source, cancellationToken)
             {
-                this.comparer = comparer;
+                this.source = source;
                 this.keySelector = keySelector;
-                this.first = true;
+                this.comparer = comparer;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override bool TryMoveNextCore(bool sourceHasCurrent, out bool result)
+            public TSource Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                if (sourceHasCurrent)
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
+            }
+
+            void MoveNext()
+            {
+                REPEAT:
+                try
                 {
-                    var v = SourceCurrent;
-                    var key = keySelector(v);
-                    if (first || !comparer.Equals(prev, key))
+                    switch (state)
                     {
-                        first = false;
-                        prev = key;
-                        Current = v;
-                        result = true;
-                        return true;
-                    }
-                    else
-                    {
-                        result = default;
-                        return false;
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case -3;
+                            }
+                            else
+                            {
+                                state = -3;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case -3: // first
+                            if (awaiter.GetResult())
+                            {
+                                Current = enumerator.Current;
+                                goto CONTINUE;
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 0: // normal
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                var v = enumerator.Current;
+                                var key = keySelector(v);
+                                if (!comparer.Equals(prev, key))
+                                {
+                                    prev = key;
+                                    Current = v;
+                                    goto CONTINUE;
+                                }
+                                else
+                                {
+                                    state = 0;
+                                    goto REPEAT;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case -2:
+                        default:
+                            goto DONE;
                     }
                 }
+                catch (Exception ex)
+                {
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
+                }
 
-                result = false;
-                return true;
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
@@ -197,42 +362,142 @@ namespace Cysharp.Threading.Tasks.Linq
             return new _DistinctUntilChangedAwait(source, keySelector, comparer, cancellationToken);
         }
 
-        class _DistinctUntilChangedAwait : AsyncEnumeratorAwaitSelectorBase<TSource, TSource, TKey>
+        sealed class _DistinctUntilChangedAwait : MoveNextSource, IUniTaskAsyncEnumerator<TSource>
         {
-            readonly IEqualityComparer<TKey> comparer;
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, UniTask<TKey>> keySelector;
+            readonly IEqualityComparer<TKey> comparer;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            UniTask<TKey>.Awaiter awaiter2;
+            Action moveNextAction;
+            TSource enumeratorCurrent;
             TKey prev;
-            bool first;
 
             public _DistinctUntilChangedAwait(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, UniTask<TKey>> keySelector, IEqualityComparer<TKey> comparer, CancellationToken cancellationToken)
-
-                : base(source, cancellationToken)
             {
-                this.comparer = comparer;
+                this.source = source;
                 this.keySelector = keySelector;
-                this.first = true;
+                this.comparer = comparer;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override UniTask<TKey> TransformAsync(TSource sourceCurrent)
+            public TSource Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                return keySelector(sourceCurrent);
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
             }
 
-            protected override bool TrySetCurrentCore(TKey key, out bool terminateIteration)
+            void MoveNext()
             {
-                if (first || !comparer.Equals(prev, key))
+                REPEAT:
+                try
                 {
-                    first = false;
-                    prev = key;
-                    Current = SourceCurrent;
-                    terminateIteration = false;
-                    return true;
+                    switch (state)
+                    {
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case -3;
+                            }
+                            else
+                            {
+                                state = -3;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case -3: // first
+                            if (awaiter.GetResult())
+                            {
+                                Current = enumerator.Current;
+                                goto CONTINUE;
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 0: // normal
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                enumeratorCurrent = enumerator.Current;
+                                awaiter2 = keySelector(enumeratorCurrent).GetAwaiter();
+                                if (awaiter2.IsCompleted)
+                                {
+                                    goto case 2;
+                                }
+                                else
+                                {
+                                    state = 2;
+                                    awaiter2.UnsafeOnCompleted(moveNextAction);
+                                    return;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 2:
+                            var key = awaiter2.GetResult();
+                            if (!comparer.Equals(prev, key))
+                            {
+                                prev = key;
+                                Current = enumeratorCurrent;
+                                goto CONTINUE;
+                            }
+                            else
+                            {
+                                state = 0;
+                                goto REPEAT;
+                            }
+                        case -2:
+                        default:
+                            goto DONE;
+                    }
                 }
-                else
+                catch (Exception ex)
                 {
-                    terminateIteration = false;
-                    return false;
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
                 }
+
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
@@ -255,42 +520,142 @@ namespace Cysharp.Threading.Tasks.Linq
             return new _DistinctUntilChangedAwaitWithCancellation(source, keySelector, comparer, cancellationToken);
         }
 
-        class _DistinctUntilChangedAwaitWithCancellation : AsyncEnumeratorAwaitSelectorBase<TSource, TSource, TKey>
+        sealed class _DistinctUntilChangedAwaitWithCancellation : MoveNextSource, IUniTaskAsyncEnumerator<TSource>
         {
-            readonly IEqualityComparer<TKey> comparer;
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, CancellationToken, UniTask<TKey>> keySelector;
+            readonly IEqualityComparer<TKey> comparer;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            UniTask<TKey>.Awaiter awaiter2;
+            Action moveNextAction;
+            TSource enumeratorCurrent;
             TKey prev;
-            bool first;
 
             public _DistinctUntilChangedAwaitWithCancellation(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, UniTask<TKey>> keySelector, IEqualityComparer<TKey> comparer, CancellationToken cancellationToken)
-
-                : base(source, cancellationToken)
             {
-                this.comparer = comparer;
+                this.source = source;
                 this.keySelector = keySelector;
-                this.first = true;
+                this.comparer = comparer;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override UniTask<TKey> TransformAsync(TSource sourceCurrent)
+            public TSource Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                return keySelector(sourceCurrent, cancellationToken);
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
             }
 
-            protected override bool TrySetCurrentCore(TKey key, out bool terminateIteration)
+            void MoveNext()
             {
-                if (first || !comparer.Equals(prev, key))
+                REPEAT:
+                try
                 {
-                    first = false;
-                    prev = key;
-                    Current = SourceCurrent;
-                    terminateIteration = false;
-                    return true;
+                    switch (state)
+                    {
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case -3;
+                            }
+                            else
+                            {
+                                state = -3;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case -3: // first
+                            if (awaiter.GetResult())
+                            {
+                                Current = enumerator.Current;
+                                goto CONTINUE;
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 0: // normal
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                enumeratorCurrent = enumerator.Current;
+                                awaiter2 = keySelector(enumeratorCurrent, cancellationToken).GetAwaiter();
+                                if (awaiter2.IsCompleted)
+                                {
+                                    goto case 2;
+                                }
+                                else
+                                {
+                                    state = 2;
+                                    awaiter2.UnsafeOnCompleted(moveNextAction);
+                                    return;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 2:
+                            var key = awaiter2.GetResult();
+                            if (!comparer.Equals(prev, key))
+                            {
+                                prev = key;
+                                Current = enumeratorCurrent;
+                                goto CONTINUE;
+                            }
+                            else
+                            {
+                                state = 0;
+                                goto REPEAT;
+                            }
+                        case -2:
+                        default:
+                            goto DONE;
+                    }
                 }
-                else
+                catch (Exception ex)
                 {
-                    terminateIteration = false;
-                    return false;
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
                 }
+
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }

src/UniTask/Assets/Plugins/UniTask/Runtime/Linq/Publish.cs

@@ -115,6 +115,8 @@ namespace Cysharp.Threading.Tasks.Linq
             }
 
             public TSource Current { get; private set; }
+            ITriggerHandler<TSource> ITriggerHandler<TSource>.Prev { get; set; }
+            ITriggerHandler<TSource> ITriggerHandler<TSource>.Next { get; set; }
 
             public UniTask<bool> MoveNextAsync()
             {

src/UniTask/Assets/Plugins/UniTask/Runtime/Linq/Select.cs

@@ -71,29 +71,92 @@ namespace Cysharp.Threading.Tasks.Linq
             return new _Select(source, selector, cancellationToken);
         }
 
-        sealed class _Select : AsyncEnumeratorBase<TSource, TResult>
+        sealed class _Select : MoveNextSource, IUniTaskAsyncEnumerator<TResult>
         {
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, TResult> selector;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            Action moveNextAction;
 
             public _Select(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, TResult> selector, CancellationToken cancellationToken)
-                : base(source, cancellationToken)
             {
+                this.source = source;
                 this.selector = selector;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override bool TryMoveNextCore(bool sourceHasCurrent, out bool result)
+            public TResult Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                if (sourceHasCurrent)
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
+            }
+
+            void MoveNext()
+            {
+                try
                 {
-                    Current = selector(SourceCurrent);
-                    result = true;
-                    return true;
+                    switch (state)
+                    {
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            goto case 0;
+                        case 0:
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                Current = selector(enumerator.Current);
+                                goto CONTINUE;
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        default:
+                            goto DONE;
+                    }
                 }
-                else
+                catch (Exception ex)
                 {
-                    result = false;
-                    return true;
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
                 }
+
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
@@ -111,33 +174,96 @@ namespace Cysharp.Threading.Tasks.Linq
 
         public IUniTaskAsyncEnumerator<TResult> GetAsyncEnumerator(CancellationToken cancellationToken = default)
         {
-            return new _SelectInt(source, selector, cancellationToken);
+            return new _Select(source, selector, cancellationToken);
         }
 
-        sealed class _SelectInt : AsyncEnumeratorBase<TSource, TResult>
+        sealed class _Select : MoveNextSource, IUniTaskAsyncEnumerator<TResult>
         {
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, int, TResult> selector;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            Action moveNextAction;
             int index;
 
-            public _SelectInt(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, int, TResult> selector, CancellationToken cancellationToken)
-                : base(source, cancellationToken)
+            public _Select(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, int, TResult> selector, CancellationToken cancellationToken)
             {
+                this.source = source;
                 this.selector = selector;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override bool TryMoveNextCore(bool sourceHasCurrent, out bool result)
+            public TResult Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                if (sourceHasCurrent)
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
+            }
+
+            void MoveNext()
+            {
+                try
                 {
-                    Current = selector(SourceCurrent, checked(index++));
-                    result = true;
-                    return true;
+                    switch (state)
+                    {
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            goto case 0;
+                        case 0:
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                Current = selector(enumerator.Current, checked(index++));
+                                goto CONTINUE;
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        default:
+                            goto DONE;
+                    }
                 }
-                else
+                catch (Exception ex)
                 {
-                    result = false;
-                    return true;
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
                 }
+
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
@@ -158,26 +284,105 @@ namespace Cysharp.Threading.Tasks.Linq
             return new _SelectAwait(source, selector, cancellationToken);
         }
 
-        sealed class _SelectAwait : AsyncEnumeratorAwaitSelectorBase<TSource, TResult, TResult>
+        sealed class _SelectAwait : MoveNextSource, IUniTaskAsyncEnumerator<TResult>
         {
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, UniTask<TResult>> selector;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            UniTask<TResult>.Awaiter awaiter2;
+            Action moveNextAction;
 
             public _SelectAwait(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, UniTask<TResult>> selector, CancellationToken cancellationToken)
-                : base(source, cancellationToken)
             {
+                this.source = source;
                 this.selector = selector;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override UniTask<TResult> TransformAsync(TSource sourceCurrent)
+            public TResult Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                return selector(sourceCurrent);
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
             }
 
-            protected override bool TrySetCurrentCore(TResult awaitResult, out bool terminateIteration)
+            void MoveNext()
             {
-                Current = awaitResult;
-                terminateIteration = false;
-                return true;
+                try
+                {
+                    switch (state)
+                    {
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            goto case 0;
+                        case 0:
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                awaiter2 = selector(enumerator.Current).GetAwaiter();
+                                if (awaiter2.IsCompleted)
+                                {
+                                    goto case 2;
+                                }
+                                else
+                                {
+                                    state = 2;
+                                    awaiter2.UnsafeOnCompleted(moveNextAction);
+                                    return;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 2:
+                            Current = awaiter2.GetResult();
+                            goto CONTINUE;
+                        default:
+                            goto DONE;
+                    }
+                }
+                catch (Exception ex)
+                {
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
+                }
+
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
@@ -195,30 +400,109 @@ namespace Cysharp.Threading.Tasks.Linq
 
         public IUniTaskAsyncEnumerator<TResult> GetAsyncEnumerator(CancellationToken cancellationToken = default)
         {
-            return new _SelectIntAwait(source, selector, cancellationToken);
+            return new _SelectAwait(source, selector, cancellationToken);
         }
 
-        sealed class _SelectIntAwait : AsyncEnumeratorAwaitSelectorBase<TSource, TResult, TResult>
+        sealed class _SelectAwait : MoveNextSource, IUniTaskAsyncEnumerator<TResult>
         {
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, int, UniTask<TResult>> selector;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            UniTask<TResult>.Awaiter awaiter2;
+            Action moveNextAction;
             int index;
 
-            public _SelectIntAwait(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, int, UniTask<TResult>> selector, CancellationToken cancellationToken)
-                : base(source, cancellationToken)
+            public _SelectAwait(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, int, UniTask<TResult>> selector, CancellationToken cancellationToken)
             {
+                this.source = source;
                 this.selector = selector;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override UniTask<TResult> TransformAsync(TSource sourceCurrent)
+            public TResult Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                return selector(sourceCurrent, checked(index++));
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
             }
 
-            protected override bool TrySetCurrentCore(TResult awaitResult, out bool terminateIteration)
+            void MoveNext()
             {
-                Current = awaitResult;
-                terminateIteration = false;
-                return true;
+                try
+                {
+                    switch (state)
+                    {
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            goto case 0;
+                        case 0:
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                awaiter2 = selector(enumerator.Current, checked(index++)).GetAwaiter();
+                                if (awaiter2.IsCompleted)
+                                {
+                                    goto case 2;
+                                }
+                                else
+                                {
+                                    state = 2;
+                                    awaiter2.UnsafeOnCompleted(moveNextAction);
+                                    return;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 2:
+                            Current = awaiter2.GetResult();
+                            goto CONTINUE;
+                        default:
+                            goto DONE;
+                    }
+                }
+                catch (Exception ex)
+                {
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
+                }
+
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
@@ -239,26 +523,105 @@ namespace Cysharp.Threading.Tasks.Linq
             return new _SelectAwaitWithCancellation(source, selector, cancellationToken);
         }
 
-        sealed class _SelectAwaitWithCancellation : AsyncEnumeratorAwaitSelectorBase<TSource, TResult, TResult>
+        sealed class _SelectAwaitWithCancellation : MoveNextSource, IUniTaskAsyncEnumerator<TResult>
         {
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, CancellationToken, UniTask<TResult>> selector;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            UniTask<TResult>.Awaiter awaiter2;
+            Action moveNextAction;
 
             public _SelectAwaitWithCancellation(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, UniTask<TResult>> selector, CancellationToken cancellationToken)
-                : base(source, cancellationToken)
             {
+                this.source = source;
                 this.selector = selector;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override UniTask<TResult> TransformAsync(TSource sourceCurrent)
+            public TResult Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                return selector(sourceCurrent, cancellationToken);
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
             }
 
-            protected override bool TrySetCurrentCore(TResult awaitResult, out bool terminateIteration)
+            void MoveNext()
             {
-                Current = awaitResult;
-                terminateIteration = false;
-                return true;
+                try
+                {
+                    switch (state)
+                    {
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            goto case 0;
+                        case 0:
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                awaiter2 = selector(enumerator.Current, cancellationToken).GetAwaiter();
+                                if (awaiter2.IsCompleted)
+                                {
+                                    goto case 2;
+                                }
+                                else
+                                {
+                                    state = 2;
+                                    awaiter2.UnsafeOnCompleted(moveNextAction);
+                                    return;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 2:
+                            Current = awaiter2.GetResult();
+                            goto CONTINUE;
+                        default:
+                            goto DONE;
+                    }
+                }
+                catch (Exception ex)
+                {
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
+                }
+
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
@@ -276,32 +639,110 @@ namespace Cysharp.Threading.Tasks.Linq
 
         public IUniTaskAsyncEnumerator<TResult> GetAsyncEnumerator(CancellationToken cancellationToken = default)
         {
-            return new _SelectIntAwaitWithCancellation(source, selector, cancellationToken);
+            return new _SelectAwaitWithCancellation(source, selector, cancellationToken);
         }
 
-        sealed class _SelectIntAwaitWithCancellation : AsyncEnumeratorAwaitSelectorBase<TSource, TResult, TResult>
+        sealed class _SelectAwaitWithCancellation : MoveNextSource, IUniTaskAsyncEnumerator<TResult>
         {
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, int, CancellationToken, UniTask<TResult>> selector;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            UniTask<TResult>.Awaiter awaiter2;
+            Action moveNextAction;
             int index;
 
-            public _SelectIntAwaitWithCancellation(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, int, CancellationToken, UniTask<TResult>> selector, CancellationToken cancellationToken)
-                : base(source, cancellationToken)
+            public _SelectAwaitWithCancellation(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, int, CancellationToken, UniTask<TResult>> selector, CancellationToken cancellationToken)
             {
+                this.source = source;
                 this.selector = selector;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override UniTask<TResult> TransformAsync(TSource sourceCurrent)
+            public TResult Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                return selector(sourceCurrent, checked(index++), cancellationToken);
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
             }
 
-            protected override bool TrySetCurrentCore(TResult awaitResult, out bool terminateIteration)
+            void MoveNext()
             {
-                Current = awaitResult;
-                terminateIteration = false;
-                return true;
+                try
+                {
+                    switch (state)
+                    {
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            goto case 0;
+                        case 0:
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                awaiter2 = selector(enumerator.Current, checked(index++), cancellationToken).GetAwaiter();
+                                if (awaiter2.IsCompleted)
+                                {
+                                    goto case 2;
+                                }
+                                else
+                                {
+                                    state = 2;
+                                    awaiter2.UnsafeOnCompleted(moveNextAction);
+                                    return;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 2:
+                            Current = awaiter2.GetResult();
+                            goto CONTINUE;
+                        default:
+                            goto DONE;
+                    }
+                }
+                catch (Exception ex)
+                {
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
+                }
+
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
-
 }

src/UniTask/Assets/Plugins/UniTask/Runtime/Linq/UniTask.Linq.asmdef

@@ -0,0 +1,15 @@
+{
+    "name": "UniTask.Linq",
+    "references": [
+        "UniTask"
+    ],
+    "includePlatforms": [],
+    "excludePlatforms": [],
+    "allowUnsafeCode": false,
+    "overrideReferences": false,
+    "precompiledReferences": [],
+    "autoReferenced": true,
+    "defineConstraints": [],
+    "versionDefines": [],
+    "noEngineReferences": false
+}

src/UniTask/Assets/Plugins/UniTask/Runtime/Linq/UniTask.Linq.asmdef.meta

@@ -0,0 +1,7 @@
+fileFormatVersion: 2
+guid: 5c01796d064528144a599661eaab93a6
+AssemblyDefinitionImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/UniTask/Assets/Plugins/UniTask/Runtime/Linq/Where.cs

@@ -71,36 +71,101 @@ namespace Cysharp.Threading.Tasks.Linq
             return new _Where(source, predicate, cancellationToken);
         }
 
-        class _Where : AsyncEnumeratorBase<TSource, TSource>
+        sealed class _Where : MoveNextSource, IUniTaskAsyncEnumerator<TSource>
         {
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, bool> predicate;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            Action moveNextAction;
 
             public _Where(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, bool> predicate, CancellationToken cancellationToken)
-
-                : base(source, cancellationToken)
             {
+                this.source = source;
                 this.predicate = predicate;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override bool TryMoveNextCore(bool sourceHasCurrent, out bool result)
+            public TSource Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                if (sourceHasCurrent)
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
+            }
+
+            void MoveNext()
+            {
+                REPEAT:
+                try
                 {
-                    if (predicate(SourceCurrent))
+                    switch (state)
                     {
-                        Current = SourceCurrent;
-                        result = true;
-                        return true;
-                    }
-                    else
-                    {
-                        result = default;
-                        return false;
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            goto case 0;
+                        case 0:
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                Current = enumerator.Current;
+                                if (predicate(Current))
+                                {
+                                    goto CONTINUE;
+                                }
+                                else
+                                {
+                                    state = 0;
+                                    goto REPEAT;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        default:
+                            goto DONE;
                     }
                 }
+                catch (Exception ex)
+                {
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
+                }
 
-                result = false;
-                return true;
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
@@ -118,40 +183,105 @@ namespace Cysharp.Threading.Tasks.Linq
 
         public IUniTaskAsyncEnumerator<TSource> GetAsyncEnumerator(CancellationToken cancellationToken = default)
         {
-            return new _WhereInt(source, predicate, cancellationToken);
+            return new _Where(source, predicate, cancellationToken);
         }
 
-        class _WhereInt : AsyncEnumeratorBase<TSource, TSource>
+        sealed class _Where : MoveNextSource, IUniTaskAsyncEnumerator<TSource>
         {
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, int, bool> predicate;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            Action moveNextAction;
             int index;
 
-            public _WhereInt(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, int, bool> predicate, CancellationToken cancellationToken)
-
-                : base(source, cancellationToken)
+            public _Where(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, int, bool> predicate, CancellationToken cancellationToken)
             {
+                this.source = source;
                 this.predicate = predicate;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override bool TryMoveNextCore(bool sourceHasCurrent, out bool result)
+            public TSource Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                if (sourceHasCurrent)
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
+            }
+
+            void MoveNext()
+            {
+                REPEAT:
+                try
                 {
-                    if (predicate(SourceCurrent, checked(index++)))
+                    switch (state)
                     {
-                        Current = SourceCurrent;
-                        result = true;
-                        return true;
-                    }
-                    else
-                    {
-                        result = default;
-                        return false;
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            goto case 0;
+                        case 0:
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                Current = enumerator.Current;
+                                if (predicate(Current, checked(index++)))
+                                {
+                                    goto CONTINUE;
+                                }
+                                else
+                                {
+                                    state = 0;
+                                    goto REPEAT;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        default:
+                            goto DONE;
                     }
                 }
+                catch (Exception ex)
+                {
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
+                }
 
-                result = false;
-                return true;
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
@@ -172,34 +302,115 @@ namespace Cysharp.Threading.Tasks.Linq
             return new _WhereAwait(source, predicate, cancellationToken);
         }
 
-        class _WhereAwait : AsyncEnumeratorAwaitSelectorBase<TSource, TSource, bool>
+        sealed class _WhereAwait : MoveNextSource, IUniTaskAsyncEnumerator<TSource>
         {
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, UniTask<bool>> predicate;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            UniTask<bool>.Awaiter awaiter2;
+            Action moveNextAction;
 
             public _WhereAwait(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, UniTask<bool>> predicate, CancellationToken cancellationToken)
-
-                : base(source, cancellationToken)
             {
+                this.source = source;
                 this.predicate = predicate;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override UniTask<bool> TransformAsync(TSource sourceCurrent)
+            public TSource Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                return predicate(sourceCurrent);
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
             }
 
-            protected override bool TrySetCurrentCore(bool awaitResult, out bool terminateIteration)
+            void MoveNext()
             {
-                terminateIteration = false;
-                if (awaitResult)
+                REPEAT:
+                try
                 {
-                    Current = SourceCurrent;
-                    return true;
+                    switch (state)
+                    {
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            goto case 0;
+                        case 0:
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                Current = enumerator.Current;
+
+                                awaiter2 = predicate(Current).GetAwaiter();
+                                if (awaiter2.IsCompleted)
+                                {
+                                    goto case 2;
+                                }
+                                else
+                                {
+                                    state = 2;
+                                    awaiter2.UnsafeOnCompleted(moveNextAction);
+                                    return;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 2:
+                            if (awaiter2.GetResult())
+                            {
+                                goto CONTINUE;
+                            }
+                            else
+                            {
+                                state = 0;
+                                goto REPEAT;
+                            }
+                        default:
+                            goto DONE;
+                    }
                 }
-                else
+                catch (Exception ex)
                 {
-                    return false;
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
                 }
+
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
@@ -217,44 +428,123 @@ namespace Cysharp.Threading.Tasks.Linq
 
         public IUniTaskAsyncEnumerator<TSource> GetAsyncEnumerator(CancellationToken cancellationToken = default)
         {
-            return new _WhereIntAwait(source, predicate, cancellationToken);
+            return new _WhereAwait(source, predicate, cancellationToken);
         }
 
-        class _WhereIntAwait : AsyncEnumeratorAwaitSelectorBase<TSource, TSource, bool>
+        sealed class _WhereAwait : MoveNextSource, IUniTaskAsyncEnumerator<TSource>
         {
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, int, UniTask<bool>> predicate;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            UniTask<bool>.Awaiter awaiter2;
+            Action moveNextAction;
             int index;
 
-            public _WhereIntAwait(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, int, UniTask<bool>> predicate, CancellationToken cancellationToken)
-
-                : base(source, cancellationToken)
+            public _WhereAwait(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, int, UniTask<bool>> predicate, CancellationToken cancellationToken)
             {
+                this.source = source;
                 this.predicate = predicate;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override UniTask<bool> TransformAsync(TSource sourceCurrent)
+            public TSource Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                return predicate(sourceCurrent, checked(index++));
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
             }
 
-            protected override bool TrySetCurrentCore(bool awaitResult, out bool terminateIteration)
+            void MoveNext()
             {
-                terminateIteration = false;
-                if (awaitResult)
+                REPEAT:
+                try
                 {
-                    Current = SourceCurrent;
-                    return true;
+                    switch (state)
+                    {
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            goto case 0;
+                        case 0:
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                Current = enumerator.Current;
+
+                                awaiter2 = predicate(Current, checked(index++)).GetAwaiter();
+                                if (awaiter2.IsCompleted)
+                                {
+                                    goto case 2;
+                                }
+                                else
+                                {
+                                    state = 2;
+                                    awaiter2.UnsafeOnCompleted(moveNextAction);
+                                    return;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 2:
+                            if (awaiter2.GetResult())
+                            {
+                                goto CONTINUE;
+                            }
+                            else
+                            {
+                                state = 0;
+                                goto REPEAT;
+                            }
+                        default:
+                            goto DONE;
+                    }
                 }
-                else
+                catch (Exception ex)
                 {
-                    return false;
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
                 }
+
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
 
-
-
     internal sealed class WhereAwaitWithCancellation<TSource> : IUniTaskAsyncEnumerable<TSource>
     {
         readonly IUniTaskAsyncEnumerable<TSource> source;
@@ -271,34 +561,115 @@ namespace Cysharp.Threading.Tasks.Linq
             return new _WhereAwaitWithCancellation(source, predicate, cancellationToken);
         }
 
-        class _WhereAwaitWithCancellation : AsyncEnumeratorAwaitSelectorBase<TSource, TSource, bool>
+        sealed class _WhereAwaitWithCancellation : MoveNextSource, IUniTaskAsyncEnumerator<TSource>
         {
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, CancellationToken, UniTask<bool>> predicate;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            UniTask<bool>.Awaiter awaiter2;
+            Action moveNextAction;
 
             public _WhereAwaitWithCancellation(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, UniTask<bool>> predicate, CancellationToken cancellationToken)
-
-                : base(source, cancellationToken)
             {
+                this.source = source;
                 this.predicate = predicate;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override UniTask<bool> TransformAsync(TSource sourceCurrent)
+            public TSource Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                return predicate(sourceCurrent, cancellationToken);
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
             }
 
-            protected override bool TrySetCurrentCore(bool awaitResult, out bool terminateIteration)
+            void MoveNext()
             {
-                terminateIteration = false;
-                if (awaitResult)
+                REPEAT:
+                try
                 {
-                    Current = SourceCurrent;
-                    return true;
+                    switch (state)
+                    {
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            goto case 0;
+                        case 0:
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                Current = enumerator.Current;
+
+                                awaiter2 = predicate(Current, cancellationToken).GetAwaiter();
+                                if (awaiter2.IsCompleted)
+                                {
+                                    goto case 2;
+                                }
+                                else
+                                {
+                                    state = 2;
+                                    awaiter2.UnsafeOnCompleted(moveNextAction);
+                                    return;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 2:
+                            if (awaiter2.GetResult())
+                            {
+                                goto CONTINUE;
+                            }
+                            else
+                            {
+                                state = 0;
+                                goto REPEAT;
+                            }
+                        default:
+                            goto DONE;
+                    }
                 }
-                else
+                catch (Exception ex)
                 {
-                    return false;
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
                 }
+
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
@@ -316,40 +687,120 @@ namespace Cysharp.Threading.Tasks.Linq
 
         public IUniTaskAsyncEnumerator<TSource> GetAsyncEnumerator(CancellationToken cancellationToken = default)
         {
-            return new _WhereIntAwaitWithCancellation(source, predicate, cancellationToken);
+            return new _WhereAwaitWithCancellation(source, predicate, cancellationToken);
         }
 
-        class _WhereIntAwaitWithCancellation : AsyncEnumeratorAwaitSelectorBase<TSource, TSource, bool>
+        sealed class _WhereAwaitWithCancellation : MoveNextSource, IUniTaskAsyncEnumerator<TSource>
         {
+            readonly IUniTaskAsyncEnumerable<TSource> source;
             readonly Func<TSource, int, CancellationToken, UniTask<bool>> predicate;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            IUniTaskAsyncEnumerator<TSource> enumerator;
+            UniTask<bool>.Awaiter awaiter;
+            UniTask<bool>.Awaiter awaiter2;
+            Action moveNextAction;
             int index;
 
-            public _WhereIntAwaitWithCancellation(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, int, CancellationToken, UniTask<bool>> predicate, CancellationToken cancellationToken)
-
-                : base(source, cancellationToken)
+            public _WhereAwaitWithCancellation(IUniTaskAsyncEnumerable<TSource> source, Func<TSource, int, CancellationToken, UniTask<bool>> predicate, CancellationToken cancellationToken)
             {
+                this.source = source;
                 this.predicate = predicate;
+                this.cancellationToken = cancellationToken;
+                this.moveNextAction = MoveNext;
             }
 
-            protected override UniTask<bool> TransformAsync(TSource sourceCurrent)
+            public TSource Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
             {
-                return predicate(sourceCurrent, checked(index++), cancellationToken);
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
             }
 
-            protected override bool TrySetCurrentCore(bool awaitResult, out bool terminateIteration)
+            void MoveNext()
             {
-                terminateIteration = false;
-                if (awaitResult)
+                REPEAT:
+                try
                 {
-                    Current = SourceCurrent;
-                    return true;
+                    switch (state)
+                    {
+                        case -1: // init
+                            enumerator = source.GetAsyncEnumerator(cancellationToken);
+                            goto case 0;
+                        case 0:
+                            awaiter = enumerator.MoveNextAsync().GetAwaiter();
+                            if (awaiter.IsCompleted)
+                            {
+                                goto case 1;
+                            }
+                            else
+                            {
+                                state = 1;
+                                awaiter.UnsafeOnCompleted(moveNextAction);
+                                return;
+                            }
+                        case 1:
+                            if (awaiter.GetResult())
+                            {
+                                Current = enumerator.Current;
+
+                                awaiter2 = predicate(Current, checked(index++), cancellationToken).GetAwaiter();
+                                if (awaiter2.IsCompleted)
+                                {
+                                    goto case 2;
+                                }
+                                else
+                                {
+                                    state = 2;
+                                    awaiter2.UnsafeOnCompleted(moveNextAction);
+                                    return;
+                                }
+                            }
+                            else
+                            {
+                                goto DONE;
+                            }
+                        case 2:
+                            if (awaiter2.GetResult())
+                            {
+                                goto CONTINUE;
+                            }
+                            else
+                            {
+                                state = 0;
+                                goto REPEAT;
+                            }
+                        default:
+                            goto DONE;
+                    }
                 }
-                else
+                catch (Exception ex)
                 {
-                    return false;
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
                 }
+
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+
+                CONTINUE:
+                state = 0;
+                completionSource.TrySetResult(true);
+                return;
+            }
+
+            public UniTask DisposeAsync()
+            {
+                return enumerator.DisposeAsync();
             }
         }
     }
-
 }

src/UniTask/Assets/Plugins/UniTask/Runtime/MoveNextSource.cs

@@ -0,0 +1,63 @@
+using System;
+
+namespace Cysharp.Threading.Tasks
+{
+    public abstract class MoveNextSource : IUniTaskSource<bool>
+    {
+        protected UniTaskCompletionSourceCore<bool> completionSource;
+
+        public bool GetResult(short token)
+        {
+            return completionSource.GetResult(token);
+        }
+
+        public UniTaskStatus GetStatus(short token)
+        {
+            return completionSource.GetStatus(token);
+        }
+
+        public void OnCompleted(Action<object> continuation, object state, short token)
+        {
+            completionSource.OnCompleted(continuation, state, token);
+        }
+
+        public UniTaskStatus UnsafeGetStatus()
+        {
+            return completionSource.UnsafeGetStatus();
+        }
+
+        void IUniTaskSource.GetResult(short token)
+        {
+            completionSource.GetResult(token);
+        }
+
+        protected bool TryGetResult<T>(UniTask<T>.Awaiter awaiter, out T result)
+        {
+            try
+            {
+                result = awaiter.GetResult();
+                return true;
+            }
+            catch (Exception ex)
+            {
+                completionSource.TrySetException(ex);
+                result = default;
+                return false;
+            }
+        }
+
+        protected bool TryGetResult(UniTask.Awaiter awaiter)
+        {
+            try
+            {
+                awaiter.GetResult();
+                return true;
+            }
+            catch (Exception ex)
+            {
+                completionSource.TrySetException(ex);
+                return false;
+            }
+        }
+    }
+}

src/UniTask/Assets/Plugins/UniTask/Runtime/MoveNextSource.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: dc4c5dc2a5f246e4f8df44cab735826c
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/UniTask/Assets/Plugins/UniTask/Runtime/PlayerLoopHelper.cs

@@ -200,27 +200,43 @@ namespace Cysharp.Threading.Tasks
 
 
 #if UNITY_EDITOR
+
         [InitializeOnLoadMethod]
         static void InitOnEditor()
         {
-            //Execute the play mode init method
+            // Execute the play mode init method
             Init();
 
-            //register an Editor update delegate, used to forcing playerLoop update
+            // register an Editor update delegate, used to forcing playerLoop update
             EditorApplication.update += ForceEditorPlayerLoopUpdate;
         }
 
         private static void ForceEditorPlayerLoopUpdate()
         {
-            if (EditorApplication.isPlayingOrWillChangePlaymode || EditorApplication.isCompiling ||
-                EditorApplication.isUpdating)
+            if (EditorApplication.isPlayingOrWillChangePlaymode || EditorApplication.isCompiling || EditorApplication.isUpdating)
             {
                 // Not in Edit mode, don't interfere
                 return;
             }
 
-            //force unity to update PlayerLoop callbacks
-            EditorApplication.QueuePlayerLoopUpdate();
+            // EditorApplication.QueuePlayerLoopUpdate causes performance issue, don't call directly.
+            // EditorApplication.QueuePlayerLoopUpdate();
+
+            if (yielders != null)
+            {
+                foreach (var item in yielders)
+                {
+                    if (item != null) item.Run();
+                }
+            }
+
+            if (runners != null)
+            {
+                foreach (var item in runners)
+                {
+                    if (item != null) item.Run();
+                }
+            }
         }
 
 #endif

src/UniTask/Assets/Plugins/UniTask/Runtime/TaskPool.cs

@@ -0,0 +1,115 @@
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Threading;
+
+namespace Cysharp.Threading.Tasks
+{
+    // internaly used but public, allow to user create custom operator with pooling.
+
+    public static class TaskPool
+    {
+        internal static int MaxPoolSize;
+        static ConcurrentDictionary<Type, Func<int>> sizes = new ConcurrentDictionary<Type, Func<int>>();
+
+        static TaskPool()
+        {
+            try
+            {
+                var value = Environment.GetEnvironmentVariable("UNITASK_MAX_POOLSIZE");
+                if (value != null)
+                {
+                    if (int.TryParse(value, out var size))
+                    {
+                        MaxPoolSize = size;
+                        return;
+                    }
+                }
+            }
+            catch { }
+
+            MaxPoolSize = int.MaxValue;
+        }
+
+        public static void SetMaxPoolSize(int maxPoolSize)
+        {
+            MaxPoolSize = maxPoolSize;
+        }
+
+        public static IEnumerable<(Type, int)> GetCacheSizeInfo()
+        {
+            foreach (var item in sizes)
+            {
+                yield return (item.Key, item.Value());
+            }
+        }
+
+        public static void RegisterSizeGetter(Type type, Func<int> getSize)
+        {
+            sizes[type] = getSize;
+        }
+    }
+
+
+    public interface ITaskPoolNode<T>
+    {
+        T NextNode { get; set; }
+    }
+
+    // mutable struct, don't mark readonly.
+    [StructLayout(LayoutKind.Auto)]
+    public struct TaskPool<T>
+        where T : class, ITaskPoolNode<T>
+    {
+        int gate;
+        int size;
+        T root;
+
+        public int Size => size;
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public bool TryPop(out T result)
+        {
+            if (Interlocked.CompareExchange(ref gate, 1, 0) == 0)
+            {
+                var v = root;
+                if (!(v is null))
+                {
+                    root = v.NextNode;
+                    v.NextNode = null;
+                    size--;
+                    result = v;
+                    Volatile.Write(ref gate, 0);
+                    return true;
+                }
+
+                Volatile.Write(ref gate, 0);
+            }
+            result = default;
+            return false;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public bool TryPush(T item)
+        {
+            if (Interlocked.CompareExchange(ref gate, 1, 0) == 0)
+            {
+                if (size < TaskPool.MaxPoolSize)
+                {
+                    item.NextNode = root;
+                    root = item;
+                    size++;
+                    Volatile.Write(ref gate, 0);
+                    return true;
+                }
+                else
+                {
+                    Volatile.Write(ref gate, 0);
+                }
+            }
+            return false;
+        }
+    }
+}

src/UniTask/Assets/Plugins/UniTask/Runtime/TaskPool.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 19f4e6575150765449cc99f25f06f25f
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/UniTask/Assets/Plugins/UniTask/Runtime/TriggerEvent.cs

@@ -1,5 +1,4 @@
-using Cysharp.Threading.Tasks.Internal;
-using System;
+using System;
 using System.Threading;
 
 namespace Cysharp.Threading.Tasks
@@ -10,341 +9,302 @@ namespace Cysharp.Threading.Tasks
         void OnError(Exception ex);
         void OnCompleted();
         void OnCanceled(CancellationToken cancellationToken);
+
+        // set/get from TriggerEvent<T>
+        ITriggerHandler<T> Prev { get; set; }
+        ITriggerHandler<T> Next { get; set; }
     }
 
     // be careful to use, itself is struct.
     public struct TriggerEvent<T>
     {
-        // optimize: many cases, handler is single.
-        ITriggerHandler<T> singleHandler;
+        ITriggerHandler<T> head; // head.prev is last
+        ITriggerHandler<T> iteratingHead;
 
-        ITriggerHandler<T>[] handlers;
+        bool preserveRemoveSelf;
+        ITriggerHandler<T> iteratingNode;
 
-        // when running(in TrySetResult), does not add immediately(trampoline).
-        bool isRunning;
-        ITriggerHandler<T> waitHandler;
-        MinimumQueue<ITriggerHandler<T>> waitQueue;
+        void LogError(Exception ex)
+        {
+#if UNITY_2018_3_OR_NEWER
+            UnityEngine.Debug.LogException(ex);
+#else
+            Console.WriteLine(ex);
+#endif
+        }
 
         public void SetResult(T value)
         {
-            isRunning = true;
-
-            if (singleHandler != null)
+            if (iteratingNode != null)
             {
+                throw new InvalidOperationException("Can not trigger itself in iterating.");
+            }
+
+            var h = head;
+            while (h != null)
+            {
+                iteratingNode = h;
+
                 try
                 {
-                    singleHandler.OnNext(value);
+                    h.OnNext(value);
                 }
                 catch (Exception ex)
                 {
-#if UNITY_2018_3_OR_NEWER
-                    UnityEngine.Debug.LogException(ex);
-#else
-                    Console.WriteLine(ex);
-#endif
+                    LogError(ex);
+                    Remove(h);
                 }
-            }
 
-            if (handlers != null)
-            {
-                for (int i = 0; i < handlers.Length; i++)
+                if (preserveRemoveSelf)
                 {
-                    if (handlers[i] != null)
-                    {
-                        try
-                        {
-                            handlers[i].OnNext(value);
-                        }
-                        catch (Exception ex)
-                        {
-                            handlers[i] = null;
-#if UNITY_2018_3_OR_NEWER
-                            UnityEngine.Debug.LogException(ex);
-#else
-                            Console.WriteLine(ex);
-#endif
-                        }
-                    }
+                    preserveRemoveSelf = false;
+                    iteratingNode = null;
+                    var next = h.Next;
+                    Remove(h);
+                    h = next;
                 }
-            }
-
-            isRunning = false;
-
-            if (waitHandler != null)
-            {
-                var h = waitHandler;
-                waitHandler = null;
-                Add(h);
-            }
-
-            if (waitQueue != null)
-            {
-                while (waitQueue.Count != 0)
+                else
                 {
-                    Add(waitQueue.Dequeue());
+                    h = h.Next;
                 }
             }
+
+            iteratingNode = null;
+            if (iteratingHead != null)
+            {
+                Add(iteratingHead);
+                iteratingHead = null;
+            }
         }
 
         public void SetCanceled(CancellationToken cancellationToken)
         {
-            isRunning = true;
-
-            if (singleHandler != null)
+            if (iteratingNode != null)
             {
+                throw new InvalidOperationException("Can not trigger itself in iterating.");
+            }
+
+            var h = head;
+            while (h != null)
+            {
+                iteratingNode = h;
                 try
                 {
-                    (singleHandler).OnCanceled(cancellationToken);
+                    h.OnCanceled(cancellationToken);
                 }
                 catch (Exception ex)
                 {
-#if UNITY_2018_3_OR_NEWER
-                    UnityEngine.Debug.LogException(ex);
-#else
-                    Console.WriteLine(ex);
-#endif
+                    LogError(ex);
                 }
+
+                preserveRemoveSelf = false;
+                iteratingNode = null;
+                var next = h.Next;
+                Remove(h);
+                h = next;
             }
 
-            if (handlers != null)
+            iteratingNode = null;
+            if (iteratingHead != null)
             {
-                for (int i = 0; i < handlers.Length; i++)
-                {
-                    if (handlers[i] != null)
-                    {
-                        try
-                        {
-                            (handlers[i]).OnCanceled(cancellationToken);
-                        }
-                        catch (Exception ex)
-                        {
-#if UNITY_2018_3_OR_NEWER
-                            UnityEngine.Debug.LogException(ex);
-#else
-                            Console.WriteLine(ex);
-#endif
-                            handlers[i] = null;
-                        }
-                    }
-                }
-            }
-
-            isRunning = false;
-
-            if (waitHandler != null)
-            {
-                var h = waitHandler;
-                waitHandler = null;
-                Add(h);
-            }
-
-            if (waitQueue != null)
-            {
-                while (waitQueue.Count != 0)
-                {
-                    Add(waitQueue.Dequeue());
-                }
+                Add(iteratingHead);
+                iteratingHead = null;
             }
         }
 
         public void SetCompleted()
         {
-            isRunning = true;
-
-            if (singleHandler != null)
+            if (iteratingNode != null)
             {
+                throw new InvalidOperationException("Can not trigger itself in iterating.");
+            }
+
+            var h = head;
+            while (h != null)
+            {
+                iteratingNode = h;
                 try
                 {
-                    (singleHandler).OnCompleted();
+                    h.OnCompleted();
                 }
                 catch (Exception ex)
                 {
-#if UNITY_2018_3_OR_NEWER
-                    UnityEngine.Debug.LogException(ex);
-#else
-                    Console.WriteLine(ex);
-#endif
+                    LogError(ex);
                 }
+
+                preserveRemoveSelf = false;
+                iteratingNode = null;
+                var next = h.Next;
+                Remove(h);
+                h = next;
             }
 
-            if (handlers != null)
+            iteratingNode = null;
+            if (iteratingHead != null)
             {
-                for (int i = 0; i < handlers.Length; i++)
-                {
-                    if (handlers[i] != null)
-                    {
-                        try
-                        {
-                            (handlers[i]).OnCompleted();
-                        }
-                        catch (Exception ex)
-                        {
-#if UNITY_2018_3_OR_NEWER
-                            UnityEngine.Debug.LogException(ex);
-#else
-                            Console.WriteLine(ex);
-#endif
-                            handlers[i] = null;
-                        }
-                    }
-                }
-            }
-
-            isRunning = false;
-
-            if (waitHandler != null)
-            {
-                var h = waitHandler;
-                waitHandler = null;
-                Add(h);
-            }
-
-            if (waitQueue != null)
-            {
-                while (waitQueue.Count != 0)
-                {
-                    Add(waitQueue.Dequeue());
-                }
+                Add(iteratingHead);
+                iteratingHead = null;
             }
         }
 
         public void SetError(Exception exception)
         {
-            isRunning = true;
-
-            if (singleHandler != null)
+            if (iteratingNode != null)
             {
+                throw new InvalidOperationException("Can not trigger itself in iterating.");
+            }
+
+            var h = head;
+            while (h != null)
+            {
+                iteratingNode = h;
                 try
                 {
-                    singleHandler.OnError(exception);
+                    h.OnError(exception);
                 }
                 catch (Exception ex)
                 {
-#if UNITY_2018_3_OR_NEWER
-                    UnityEngine.Debug.LogException(ex);
-#else
-                    Console.WriteLine(ex);
-#endif
+                    LogError(ex);
                 }
+
+                preserveRemoveSelf = false;
+                iteratingNode = null;
+                var next = h.Next;
+                Remove(h);
+                h = next;
             }
 
-            if (handlers != null)
+            iteratingNode = null;
+            if (iteratingHead != null)
             {
-                for (int i = 0; i < handlers.Length; i++)
-                {
-                    if (handlers[i] != null)
-                    {
-                        try
-                        {
-                            handlers[i].OnError(exception);
-                        }
-                        catch (Exception ex)
-                        {
-                            handlers[i] = null;
-#if UNITY_2018_3_OR_NEWER
-                            UnityEngine.Debug.LogException(ex);
-#else
-                            Console.WriteLine(ex);
-#endif
-                        }
-                    }
-                }
-            }
-
-            isRunning = false;
-
-            if (waitHandler != null)
-            {
-                var h = waitHandler;
-                waitHandler = null;
-                Add(h);
-            }
-
-            if (waitQueue != null)
-            {
-                while (waitQueue.Count != 0)
-                {
-                    Add(waitQueue.Dequeue());
-                }
+                Add(iteratingHead);
+                iteratingHead = null;
             }
         }
 
         public void Add(ITriggerHandler<T> handler)
         {
-            if (isRunning)
-            {
-                if (waitHandler == null)
-                {
-                    waitHandler = handler;
-                    return;
-                }
+            if (handler == null) throw new ArgumentNullException(nameof(handler));
 
-                if (waitQueue == null)
-                {
-                    waitQueue = new MinimumQueue<ITriggerHandler<T>>(4);
-                }
-                waitQueue.Enqueue(handler);
+            // zero node.
+            if (head == null)
+            {
+                head = handler;
                 return;
             }
 
-            if (singleHandler == null)
+            if (iteratingNode != null)
             {
-                singleHandler = handler;
+                if (iteratingHead == null)
+                {
+                    iteratingHead = handler;
+                    return;
+                }
+
+                var last = iteratingHead.Prev;
+                if (last == null)
+                {
+                    // single node.
+                    iteratingHead.Prev = handler;
+                    iteratingHead.Next = handler;
+                    handler.Prev = iteratingHead;
+                }
+                else
+                {
+                    // multi node
+                    iteratingHead.Prev = handler;
+                    last.Next = handler;
+                    handler.Prev = last;
+                }
             }
             else
             {
-                if (handlers == null)
+                var last = head.Prev;
+                if (last == null)
                 {
-                    handlers = new ITriggerHandler<T>[4];
+                    // single node.
+                    head.Prev = handler;
+                    head.Next = handler;
+                    handler.Prev = head;
                 }
-
-                // check empty
-                for (int i = 0; i < handlers.Length; i++)
+                else
                 {
-                    if (handlers[i] == null)
-                    {
-                        handlers[i] = handler;
-                        return;
-                    }
-                }
-
-                // full, ensure capacity
-                var last = handlers.Length;
-                {
-                    EnsureCapacity(ref handlers);
-                    handlers[last] = handler;
+                    // multi node
+                    head.Prev = handler;
+                    last.Next = handler;
+                    handler.Prev = last;
                 }
             }
         }
 
-        static void EnsureCapacity(ref ITriggerHandler<T>[] array)
-        {
-            var newSize = array.Length * 2;
-            var newArray = new ITriggerHandler<T>[newSize];
-            Array.Copy(array, 0, newArray, 0, array.Length);
-            array = newArray;
-        }
-
         public void Remove(ITriggerHandler<T> handler)
         {
-            if (singleHandler == handler)
+            if (handler == null) throw new ArgumentNullException(nameof(handler));
+
+            if (iteratingNode != null && iteratingNode == handler)
             {
-                singleHandler = null;
+                // if remove self, reserve remove self after invoke completed.
+                preserveRemoveSelf = true;
             }
             else
             {
-                if (handlers != null)
+                var prev = handler.Prev;
+                var next = handler.Next;
+
+                if (next != null)
                 {
-                    for (int i = 0; i < handlers.Length; i++)
+                    next.Prev = prev;
+                }
+
+                if (handler == head)
+                {
+                    head = next;
+                }
+                else if (handler == iteratingHead)
+                {
+                    iteratingHead = next;
+                }
+                else
+                {
+                    // when handler is head, prev indicate last so don't use it.
+                    if (prev != null)
                     {
-                        if (handlers[i] == handler)
+                        prev.Next = next;
+                    }
+                }
+
+                if (head != null)
+                {
+                    if (head.Prev == handler)
+                    {
+                        if (prev != head)
                         {
-                            // fill null.
-                            handlers[i] = null;
-                            return;
+                            head.Prev = prev;
+                        }
+                        else
+                        {
+                            head.Prev = null;
                         }
                     }
                 }
+
+                if (iteratingHead != null)
+                {
+                    if (iteratingHead.Prev == handler)
+                    {
+                        if (prev != iteratingHead.Prev)
+                        {
+                            iteratingHead.Prev = prev;
+                        }
+                        else
+                        {
+                            iteratingHead.Prev = null;
+                        }
+                    }
+                }
+
+                handler.Prev = null;
+                handler.Next = null;
             }
         }
     }

src/UniTask/Assets/Plugins/UniTask/Runtime/Triggers/AsyncTriggerBase.cs

@@ -1,6 +1,5 @@
 #pragma warning disable CS1591 // Missing XML comment for publicly visible type or member
 
-using Cysharp.Threading.Tasks.Linq;
 using System;
 using System.Threading;
 using UnityEngine;
@@ -103,6 +102,8 @@ namespace Cysharp.Threading.Tasks.Triggers
             }
 
             public T Current { get; private set; }
+            ITriggerHandler<T> ITriggerHandler<T>.Prev { get; set; }
+            ITriggerHandler<T> ITriggerHandler<T>.Next { get; set; }
 
             public UniTask<bool> MoveNextAsync()
             {
@@ -189,6 +190,9 @@ namespace Cysharp.Threading.Tasks.Triggers
 
         internal CancellationToken CancellationToken => cancellationToken;
 
+        ITriggerHandler<T> ITriggerHandler<T>.Prev { get; set; }
+        ITriggerHandler<T> ITriggerHandler<T>.Next { get; set; }
+
         internal AsyncTriggerHandler(AsyncTriggerBase<T> trigger, bool callOnce)
         {
             if (cancellationToken.IsCancellationRequested)

src/UniTask/Assets/Plugins/UniTask/Runtime/UniTask.Delay.cs

@@ -56,9 +56,15 @@ namespace Cysharp.Threading.Tasks
                 : new UniTask(DelayPromise.Create(delayTimeSpan, delayTiming, cancellationToken, out token), token);
         }
 
-        sealed class YieldPromise : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        sealed class YieldPromise : IUniTaskSource, IPlayerLoopItem, ITaskPoolNode<YieldPromise>
         {
-            static readonly PromisePool<YieldPromise> pool = new PromisePool<YieldPromise>();
+            static TaskPool<YieldPromise> pool;
+            public YieldPromise NextNode { get; set; }
+
+            static YieldPromise()
+            {
+                TaskPool.RegisterSizeGetter(typeof(YieldPromise), () => pool.Size);
+            }
 
             CancellationToken cancellationToken;
             UniTaskCompletionSourceCore<object> core;
@@ -74,7 +80,11 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new YieldPromise();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new YieldPromise();
+                }
+
 
                 result.cancellationToken = cancellationToken;
 
@@ -90,12 +100,11 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
                     core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -126,24 +135,32 @@ namespace Cysharp.Threading.Tasks
                 return false;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~YieldPromise()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
             }
         }
 
-        sealed class DelayFramePromise : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        sealed class DelayFramePromise : IUniTaskSource, IPlayerLoopItem, ITaskPoolNode<DelayFramePromise>
         {
-            static readonly PromisePool<DelayFramePromise> pool = new PromisePool<DelayFramePromise>();
+            static TaskPool<DelayFramePromise> pool;
+            public DelayFramePromise NextNode { get; set; }
+
+            static DelayFramePromise()
+            {
+                TaskPool.RegisterSizeGetter(typeof(DelayFramePromise), () => pool.Size);
+            }
 
             int delayFrameCount;
             CancellationToken cancellationToken;
@@ -162,7 +179,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new DelayFramePromise();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new DelayFramePromise();
+                }
 
                 result.delayFrameCount = delayFrameCount;
                 result.cancellationToken = cancellationToken;
@@ -179,12 +199,11 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
                     core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -221,26 +240,34 @@ namespace Cysharp.Threading.Tasks
                 return true;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
                 currentFrameCount = default;
                 delayFrameCount = default;
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~DelayFramePromise()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
             }
         }
 
-        sealed class DelayPromise : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        sealed class DelayPromise : IUniTaskSource, IPlayerLoopItem, ITaskPoolNode<DelayPromise>
         {
-            static readonly PromisePool<DelayPromise> pool = new PromisePool<DelayPromise>();
+            static TaskPool<DelayPromise> pool;
+            public DelayPromise NextNode { get; set; }
+
+            static DelayPromise()
+            {
+                TaskPool.RegisterSizeGetter(typeof(DelayPromise), () => pool.Size);
+            }
 
             float delayFrameTimeSpan;
             float elapsed;
@@ -259,7 +286,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new DelayPromise();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new DelayPromise();
+                }
 
                 result.elapsed = 0.0f;
                 result.delayFrameTimeSpan = (float)delayFrameTimeSpan.TotalSeconds;
@@ -277,12 +307,11 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
                     core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -319,26 +348,34 @@ namespace Cysharp.Threading.Tasks
                 return true;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
                 delayFrameTimeSpan = default;
                 elapsed = default;
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~DelayPromise()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
             }
         }
 
-        sealed class DelayIgnoreTimeScalePromise : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        sealed class DelayIgnoreTimeScalePromise : IUniTaskSource, IPlayerLoopItem, ITaskPoolNode<DelayIgnoreTimeScalePromise>
         {
-            static readonly PromisePool<DelayIgnoreTimeScalePromise> pool = new PromisePool<DelayIgnoreTimeScalePromise>();
+            static TaskPool<DelayIgnoreTimeScalePromise> pool;
+            public DelayIgnoreTimeScalePromise NextNode { get; set; }
+
+            static DelayIgnoreTimeScalePromise()
+            {
+                TaskPool.RegisterSizeGetter(typeof(DelayIgnoreTimeScalePromise), () => pool.Size);
+            }
 
             float delayFrameTimeSpan;
             float elapsed;
@@ -357,7 +394,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new DelayIgnoreTimeScalePromise();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new DelayIgnoreTimeScalePromise();
+                }
 
                 result.elapsed = 0.0f;
                 result.delayFrameTimeSpan = (float)delayFrameTimeSpan.TotalSeconds;
@@ -375,12 +415,11 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
                     core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -417,17 +456,19 @@ namespace Cysharp.Threading.Tasks
                 return true;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
                 delayFrameTimeSpan = default;
                 elapsed = default;
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~DelayIgnoreTimeScalePromise()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }

src/UniTask/Assets/Plugins/UniTask/Runtime/UniTask.Factory.cs

@@ -1,6 +1,8 @@
 #pragma warning disable CS1591 // Missing XML comment for publicly visible type or member
 
+using Cysharp.Threading.Tasks.Internal;
 using System;
+using System.Runtime.CompilerServices;
 using System.Threading;
 
 namespace Cysharp.Threading.Tasks
@@ -102,8 +104,7 @@ namespace Cysharp.Threading.Tasks
         }
 
         /// <summary>
-        /// helper of create add UniTaskVoid to delegate.
-        /// For example: FooEvent += () => UniTask.Void(async () => { /* */ })
+        /// helper of fire and forget void action.
         /// </summary>
         public static void Void(Func<UniTaskVoid> asyncAction)
         {
@@ -111,7 +112,7 @@ namespace Cysharp.Threading.Tasks
         }
 
         /// <summary>
-        /// helper of create add UniTaskVoid to delegate.
+        /// helper of fire and forget void action.
         /// </summary>
         public static void Void(Func<CancellationToken, UniTaskVoid> asyncAction, CancellationToken cancellationToken)
         {
@@ -119,8 +120,7 @@ namespace Cysharp.Threading.Tasks
         }
 
         /// <summary>
-        /// helper of create add UniTaskVoid to delegate.
-        /// For example: FooEvent += (sender, e) => UniTask.Void(async arg => { /* */ }, (sender, e))
+        /// helper of fire and forget void action.
         /// </summary>
         public static void Void<T>(Func<T, UniTaskVoid> asyncAction, T state)
         {
@@ -204,7 +204,7 @@ namespace Cysharp.Threading.Tasks
                 if (f == null) throw new InvalidOperationException("Can't call twice.");
 
                 task = f();
-                awaiter = f().GetAwaiter();
+                awaiter = task.GetAwaiter();
                 return task.Status;
             }
 
@@ -246,7 +246,7 @@ namespace Cysharp.Threading.Tasks
                 if (f == null) throw new InvalidOperationException("Can't call twice.");
 
                 task = f();
-                awaiter = f().GetAwaiter();
+                awaiter = task.GetAwaiter();
                 return task.Status;
             }
 

src/UniTask/Assets/Plugins/UniTask/Runtime/UniTask.Threading.cs

@@ -17,7 +17,31 @@ namespace Cysharp.Threading.Tasks
         /// </summary>
         public static SwitchToMainThreadAwaitable SwitchToMainThread()
         {
-            return new SwitchToMainThreadAwaitable();
+            return new SwitchToMainThreadAwaitable(PlayerLoopTiming.Update);
+        }
+
+        /// <summary>
+        /// If running on mainthread, do nothing. Otherwise, same as UniTask.Yield(timing).
+        /// </summary>
+        public static SwitchToMainThreadAwaitable SwitchToMainThread(PlayerLoopTiming timing)
+        {
+            return new SwitchToMainThreadAwaitable(timing);
+        }
+
+        /// <summary>
+        /// Return to mainthread(same as await SwitchToMainThread) after using scope is closed.
+        /// </summary>
+        public static ReturnToMainThread ReturnToMainThread()
+        {
+            return new ReturnToMainThread(PlayerLoopTiming.Update);
+        }
+
+        /// <summary>
+        /// Return to mainthread(same as await SwitchToMainThread) after using scope is closed.
+        /// </summary>
+        public static ReturnToMainThread ReturnToMainThread(PlayerLoopTiming timing)
+        {
+            return new ReturnToMainThread(timing);
         }
 
 #endif
@@ -27,15 +51,28 @@ namespace Cysharp.Threading.Tasks
             return new SwitchToThreadPoolAwaitable();
         }
 
+        /// <summary>
+        /// Note: use SwitchToThreadPool is recommended.
+        /// </summary>
         public static SwitchToTaskPoolAwaitable SwitchToTaskPool()
         {
             return new SwitchToTaskPoolAwaitable();
         }
 
-        public static SwitchToSynchronizationContextAwaitable SwitchToSynchronizationContext(SynchronizationContext syncContext)
+        public static SwitchToSynchronizationContextAwaitable SwitchToSynchronizationContext(SynchronizationContext synchronizationContext)
         {
-            Error.ThrowArgumentNullException(syncContext, nameof(syncContext));
-            return new SwitchToSynchronizationContextAwaitable(syncContext);
+            Error.ThrowArgumentNullException(synchronizationContext, nameof(synchronizationContext));
+            return new SwitchToSynchronizationContextAwaitable(synchronizationContext);
+        }
+
+        public static ReturnToSynchronizationContext ReturnToSynchronizationContext(SynchronizationContext synchronizationContext)
+        {
+            return new ReturnToSynchronizationContext(synchronizationContext, false);
+        }
+
+        public static ReturnToSynchronizationContext ReturnToCurrentSynchronizationContext(bool dontPostWhenSameContext = true)
+        {
+            return new ReturnToSynchronizationContext(SynchronizationContext.Current, dontPostWhenSameContext);
         }
     }
 
@@ -43,10 +80,24 @@ namespace Cysharp.Threading.Tasks
 
     public struct SwitchToMainThreadAwaitable
     {
-        public Awaiter GetAwaiter() => new Awaiter();
+        readonly PlayerLoopTiming playerLoopTiming;
+
+        public SwitchToMainThreadAwaitable(PlayerLoopTiming playerLoopTiming)
+        {
+            this.playerLoopTiming = playerLoopTiming;
+        }
+
+        public Awaiter GetAwaiter() => new Awaiter(playerLoopTiming);
 
         public struct Awaiter : ICriticalNotifyCompletion
         {
+            readonly PlayerLoopTiming playerLoopTiming;
+
+            public Awaiter(PlayerLoopTiming playerLoopTiming)
+            {
+                this.playerLoopTiming = playerLoopTiming;
+            }
+
             public bool IsCompleted
             {
                 get
@@ -67,12 +118,53 @@ namespace Cysharp.Threading.Tasks
 
             public void OnCompleted(Action continuation)
             {
-                PlayerLoopHelper.AddContinuation(PlayerLoopTiming.Update, continuation);
+                PlayerLoopHelper.AddContinuation(playerLoopTiming, continuation);
             }
 
             public void UnsafeOnCompleted(Action continuation)
             {
-                PlayerLoopHelper.AddContinuation(PlayerLoopTiming.Update, continuation);
+                PlayerLoopHelper.AddContinuation(playerLoopTiming, continuation);
+            }
+        }
+    }
+
+    public struct ReturnToMainThread
+    {
+        readonly PlayerLoopTiming playerLoopTiming;
+
+        public ReturnToMainThread(PlayerLoopTiming playerLoopTiming)
+        {
+            this.playerLoopTiming = playerLoopTiming;
+        }
+
+        public Awaiter DisposeAsync()
+        {
+            return new Awaiter(playerLoopTiming); // run immediate.
+        }
+
+        public readonly struct Awaiter : ICriticalNotifyCompletion
+        {
+            readonly PlayerLoopTiming timing;
+
+            public Awaiter(PlayerLoopTiming timing)
+            {
+                this.timing = timing;
+            }
+
+            public Awaiter GetAwaiter() => this;
+
+            public bool IsCompleted => PlayerLoopHelper.MainThreadId == System.Threading.Thread.CurrentThread.ManagedThreadId;
+
+            public void GetResult() { }
+
+            public void OnCompleted(Action continuation)
+            {
+                PlayerLoopHelper.AddContinuation(timing, continuation);
+            }
+
+            public void UnsafeOnCompleted(Action continuation)
+            {
+                PlayerLoopHelper.AddContinuation(timing, continuation);
             }
         }
     }
@@ -92,12 +184,16 @@ namespace Cysharp.Threading.Tasks
 
             public void OnCompleted(Action continuation)
             {
-                ThreadPool.UnsafeQueueUserWorkItem(switchToCallback, continuation);
+                ThreadPool.QueueUserWorkItem(switchToCallback, continuation);
             }
 
             public void UnsafeOnCompleted(Action continuation)
             {
+#if NETCOREAPP3_1
+                ThreadPool.UnsafeQueueUserWorkItem(ThreadPoolWorkItem.Create(continuation), false);
+#else
                 ThreadPool.UnsafeQueueUserWorkItem(switchToCallback, continuation);
+#endif
             }
 
             static void Callback(object state)
@@ -106,6 +202,47 @@ namespace Cysharp.Threading.Tasks
                 continuation();
             }
         }
+
+#if NETCOREAPP3_1
+
+        sealed class ThreadPoolWorkItem : IThreadPoolWorkItem, ITaskPoolNode<ThreadPoolWorkItem>
+        {
+            static TaskPool<ThreadPoolWorkItem> pool;
+            public ThreadPoolWorkItem NextNode { get; set; }
+
+            static ThreadPoolWorkItem()
+            {
+                TaskPool.RegisterSizeGetter(typeof(ThreadPoolWorkItem), () => pool.Size);
+            }
+
+            Action continuation;
+
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            public static ThreadPoolWorkItem Create(Action continuation)
+            {
+                if (!pool.TryPop(out var item))
+                {
+                    item = new ThreadPoolWorkItem();
+                }
+
+                item.continuation = continuation;
+                return item;
+            }
+
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            public void Execute()
+            {
+                var call = continuation;
+                continuation = null;
+                if (call != null)
+                {
+                    pool.TryPush(this);
+                    call.Invoke();
+                }
+            }
+        }
+
+#endif
     }
 
     public struct SwitchToTaskPoolAwaitable
@@ -178,5 +315,73 @@ namespace Cysharp.Threading.Tasks
             }
         }
     }
-}
 
+    public struct ReturnToSynchronizationContext
+    {
+        readonly SynchronizationContext syncContext;
+        readonly bool dontPostWhenSameContext;
+
+        public ReturnToSynchronizationContext(SynchronizationContext syncContext, bool dontPostWhenSameContext)
+        {
+            this.syncContext = syncContext;
+            this.dontPostWhenSameContext = dontPostWhenSameContext;
+        }
+
+        public Awaiter DisposeAsync()
+        {
+            return new Awaiter(syncContext, dontPostWhenSameContext);
+        }
+
+        public struct Awaiter : ICriticalNotifyCompletion
+        {
+            static readonly SendOrPostCallback switchToCallback = Callback;
+
+            readonly SynchronizationContext synchronizationContext;
+            readonly bool dontPostWhenSameContext;
+
+            public Awaiter(SynchronizationContext synchronizationContext, bool dontPostWhenSameContext)
+            {
+                this.synchronizationContext = synchronizationContext;
+                this.dontPostWhenSameContext = dontPostWhenSameContext;
+            }
+
+            public Awaiter GetAwaiter() => this;
+
+            public bool IsCompleted
+            {
+                get
+                {
+                    if (!dontPostWhenSameContext) return false;
+
+                    var current = SynchronizationContext.Current;
+                    if (current == synchronizationContext)
+                    {
+                        return true;
+                    }
+                    else
+                    {
+                        return false;
+                    }
+                }
+            }
+
+            public void GetResult() { }
+
+            public void OnCompleted(Action continuation)
+            {
+                synchronizationContext.Post(switchToCallback, continuation);
+            }
+
+            public void UnsafeOnCompleted(Action continuation)
+            {
+                synchronizationContext.Post(switchToCallback, continuation);
+            }
+
+            static void Callback(object state)
+            {
+                var continuation = (Action)state;
+                continuation();
+            }
+        }
+    }
+}

src/UniTask/Assets/Plugins/UniTask/Runtime/UniTask.WaitUntil.cs

@@ -35,9 +35,15 @@ namespace Cysharp.Threading.Tasks
                 : WaitUntilValueChangedStandardObjectPromise<T, U>.Create(target, monitorFunction, equalityComparer, monitorTiming, cancellationToken, out token), token);
         }
 
-        sealed class WaitUntilPromise : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        sealed class WaitUntilPromise : IUniTaskSource, IPlayerLoopItem, ITaskPoolNode<WaitUntilPromise>
         {
-            static readonly PromisePool<WaitUntilPromise> pool = new PromisePool<WaitUntilPromise>();
+            static TaskPool<WaitUntilPromise> pool;
+            public WaitUntilPromise NextNode { get; set; }
+
+            static WaitUntilPromise()
+            {
+                TaskPool.RegisterSizeGetter(typeof(WaitUntilPromise), () => pool.Size);
+            }
 
             Func<bool> predicate;
             CancellationToken cancellationToken;
@@ -55,7 +61,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new WaitUntilPromise();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new WaitUntilPromise();
+                }
 
                 result.predicate = predicate;
                 result.cancellationToken = cancellationToken;
@@ -72,12 +81,11 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
                     core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -121,25 +129,33 @@ namespace Cysharp.Threading.Tasks
                 return false;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
                 predicate = default;
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~WaitUntilPromise()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
             }
         }
 
-        sealed class WaitWhilePromise : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        sealed class WaitWhilePromise : IUniTaskSource, IPlayerLoopItem, ITaskPoolNode<WaitWhilePromise>
         {
-            static readonly PromisePool<WaitWhilePromise> pool = new PromisePool<WaitWhilePromise>();
+            static TaskPool<WaitWhilePromise> pool;
+            public WaitWhilePromise NextNode { get; set; }
+
+            static WaitWhilePromise()
+            {
+                TaskPool.RegisterSizeGetter(typeof(WaitWhilePromise), () => pool.Size);
+            }
 
             Func<bool> predicate;
             CancellationToken cancellationToken;
@@ -157,7 +173,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new WaitWhilePromise();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new WaitWhilePromise();
+                }
 
                 result.predicate = predicate;
                 result.cancellationToken = cancellationToken;
@@ -174,12 +193,11 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
                     core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -223,25 +241,33 @@ namespace Cysharp.Threading.Tasks
                 return false;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
                 predicate = default;
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~WaitWhilePromise()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
             }
         }
 
-        sealed class WaitUntilCanceledPromise : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        sealed class WaitUntilCanceledPromise : IUniTaskSource, IPlayerLoopItem, ITaskPoolNode<WaitUntilCanceledPromise>
         {
-            static readonly PromisePool<WaitUntilCanceledPromise> pool = new PromisePool<WaitUntilCanceledPromise>();
+            static TaskPool<WaitUntilCanceledPromise> pool;
+            public WaitUntilCanceledPromise NextNode { get; set; }
+
+            static WaitUntilCanceledPromise()
+            {
+                TaskPool.RegisterSizeGetter(typeof(WaitUntilCanceledPromise), () => pool.Size);
+            }
 
             CancellationToken cancellationToken;
 
@@ -258,7 +284,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new WaitUntilCanceledPromise();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new WaitUntilCanceledPromise();
+                }
 
                 result.cancellationToken = cancellationToken;
 
@@ -274,12 +303,11 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
                     core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -309,15 +337,17 @@ namespace Cysharp.Threading.Tasks
                 return true;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~WaitUntilCanceledPromise()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
@@ -325,9 +355,15 @@ namespace Cysharp.Threading.Tasks
         }
 
         // where T : UnityEngine.Object, can not add constraint
-        sealed class WaitUntilValueChangedUnityObjectPromise<T, U> : IUniTaskSource<U>, IPlayerLoopItem, IPromisePoolItem
+        sealed class WaitUntilValueChangedUnityObjectPromise<T, U> : IUniTaskSource<U>, IPlayerLoopItem, ITaskPoolNode<WaitUntilValueChangedUnityObjectPromise<T, U>>
         {
-            static readonly PromisePool<WaitUntilValueChangedUnityObjectPromise<T, U>> pool = new PromisePool<WaitUntilValueChangedUnityObjectPromise<T, U>>();
+            static TaskPool<WaitUntilValueChangedUnityObjectPromise<T, U>> pool;
+            public WaitUntilValueChangedUnityObjectPromise<T, U> NextNode { get; set; }
+
+            static WaitUntilValueChangedUnityObjectPromise()
+            {
+                TaskPool.RegisterSizeGetter(typeof(WaitUntilValueChangedUnityObjectPromise<T, U>), () => pool.Size);
+            }
 
             T target;
             UnityEngine.Object targetAsUnityObject;
@@ -349,7 +385,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource<U>.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new WaitUntilValueChangedUnityObjectPromise<T, U>();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new WaitUntilValueChangedUnityObjectPromise<T, U>();
+                }
 
                 result.target = target;
                 result.targetAsUnityObject = target as UnityEngine.Object;
@@ -370,12 +409,11 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
                     return core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -426,29 +464,37 @@ namespace Cysharp.Threading.Tasks
                 return false;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
                 target = default;
                 currentValue = default;
                 monitorFunction = default;
                 equalityComparer = default;
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~WaitUntilValueChangedUnityObjectPromise()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
             }
         }
 
-        sealed class WaitUntilValueChangedStandardObjectPromise<T, U> : IUniTaskSource<U>, IPlayerLoopItem, IPromisePoolItem
+        sealed class WaitUntilValueChangedStandardObjectPromise<T, U> : IUniTaskSource<U>, IPlayerLoopItem, ITaskPoolNode<WaitUntilValueChangedStandardObjectPromise<T, U>>
             where T : class
         {
-            static readonly PromisePool<WaitUntilValueChangedStandardObjectPromise<T, U>> pool = new PromisePool<WaitUntilValueChangedStandardObjectPromise<T, U>>();
+            static TaskPool<WaitUntilValueChangedStandardObjectPromise<T, U>> pool;
+            public WaitUntilValueChangedStandardObjectPromise<T, U> NextNode { get; set; }
+
+            static WaitUntilValueChangedStandardObjectPromise()
+            {
+                TaskPool.RegisterSizeGetter(typeof(WaitUntilValueChangedStandardObjectPromise<T, U>), () => pool.Size);
+            }
 
             WeakReference<T> target;
             U currentValue;
@@ -469,7 +515,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource<U>.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new WaitUntilValueChangedStandardObjectPromise<T, U>();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new WaitUntilValueChangedStandardObjectPromise<T, U>();
+                }
 
                 result.target = new WeakReference<T>(target, false); // wrap in WeakReference.
                 result.monitorFunction = monitorFunction;
@@ -489,12 +538,11 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
                     return core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -545,19 +593,21 @@ namespace Cysharp.Threading.Tasks
                 return false;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
                 target = default;
                 currentValue = default;
                 monitorFunction = default;
                 equalityComparer = default;
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~WaitUntilValueChangedStandardObjectPromise()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }

src/UniTask/Assets/Plugins/UniTask/Runtime/UniTask.cs

@@ -1,22 +1,22 @@
 #pragma warning disable CS1591 // Missing XML comment for publicly visible type or member
 #pragma warning disable CS0436
 
+using Cysharp.Threading.Tasks.CompilerServices;
 using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Runtime.ExceptionServices;
-using Cysharp.Threading.Tasks.CompilerServices;
-using Cysharp.Threading.Tasks.Internal;
+using System.Runtime.InteropServices;
 
 namespace Cysharp.Threading.Tasks
 {
     internal static class AwaiterActions
     {
-        internal static readonly Action<object> InvokeActionDelegate = InvokeAction;
+        internal static readonly Action<object> InvokeContinuationDelegate = Continuation;
 
         [DebuggerHidden]
-        static void InvokeAction(object state)
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        static void Continuation(object state)
         {
             ((Action)state).Invoke();
         }
@@ -26,6 +26,7 @@ namespace Cysharp.Threading.Tasks
     /// Lightweight unity specified task-like object.
     /// </summary>
     [AsyncMethodBuilder(typeof(AsyncUniTaskMethodBuilder))]
+    [StructLayout(LayoutKind.Auto)]
     public readonly partial struct UniTask
     {
         readonly IUniTaskSource source;
@@ -68,6 +69,24 @@ namespace Cysharp.Threading.Tasks
             return new UniTask<bool>(new IsCanceledSource(source), token);
         }
 
+#if !UNITY_2018_3_OR_NEWER
+
+        public static implicit operator System.Threading.Tasks.ValueTask(in UniTask self)
+        {
+            if (self.source == null)
+            {
+                return default;
+            }
+
+#if NETSTANDARD2_0
+            return self.AsValueTask();
+#else
+            return new System.Threading.Tasks.ValueTask(self.source, self.token);
+#endif
+        }
+
+#endif
+
         public override string ToString()
         {
             if (source == null) return "()";
@@ -298,7 +317,7 @@ namespace Cysharp.Threading.Tasks
                 }
                 else
                 {
-                    task.source.OnCompleted(AwaiterActions.InvokeActionDelegate, continuation, task.token);
+                    task.source.OnCompleted(AwaiterActions.InvokeContinuationDelegate, continuation, task.token);
                 }
             }
 
@@ -312,7 +331,7 @@ namespace Cysharp.Threading.Tasks
                 }
                 else
                 {
-                    task.source.OnCompleted(AwaiterActions.InvokeActionDelegate, continuation, task.token);
+                    task.source.OnCompleted(AwaiterActions.InvokeContinuationDelegate, continuation, task.token);
                 }
             }
 
@@ -339,6 +358,7 @@ namespace Cysharp.Threading.Tasks
     /// Lightweight unity specified task-like object.
     /// </summary>
     [AsyncMethodBuilder(typeof(AsyncUniTaskMethodBuilder<>))]
+    [StructLayout(LayoutKind.Auto)]
     public readonly struct UniTask<T>
     {
         readonly IUniTaskSource<T> source;
@@ -414,6 +434,24 @@ namespace Cysharp.Threading.Tasks
             return self.AsUniTask();
         }
 
+#if !UNITY_2018_3_OR_NEWER
+
+        public static implicit operator System.Threading.Tasks.ValueTask<T>(in UniTask<T> self)
+        {
+            if (self.source == null)
+            {
+                return new System.Threading.Tasks.ValueTask<T>(self.result);
+            }
+
+#if NETSTANDARD2_0
+            return self.AsValueTask();
+#else
+            return new System.Threading.Tasks.ValueTask<T>(self.source, self.token);
+#endif
+        }
+
+#endif
+
         /// <summary>
         /// returns (bool IsCanceled, T Result) instead of throws OperationCanceledException.
         /// </summary>
@@ -621,7 +659,7 @@ namespace Cysharp.Threading.Tasks
                 }
                 else
                 {
-                    s.OnCompleted(AwaiterActions.InvokeActionDelegate, continuation, task.token);
+                    s.OnCompleted(AwaiterActions.InvokeContinuationDelegate, continuation, task.token);
                 }
             }
 
@@ -636,7 +674,7 @@ namespace Cysharp.Threading.Tasks
                 }
                 else
                 {
-                    s.OnCompleted(AwaiterActions.InvokeActionDelegate, continuation, task.token);
+                    s.OnCompleted(AwaiterActions.InvokeContinuationDelegate, continuation, task.token);
                 }
             }
 

src/UniTask/Assets/Plugins/UniTask/Runtime/UniTaskCompletionSource.cs

@@ -271,7 +271,7 @@ namespace Cysharp.Threading.Tasks
         {
             if (token != version)
             {
-                throw new InvalidOperationException("token version is not matched, can not await twice.");
+                throw new InvalidOperationException("Token version is not matched, can not await twice or get Status after await.");
             }
         }
     }
@@ -375,9 +375,15 @@ namespace Cysharp.Threading.Tasks
         }
     }
 
-    public class AutoResetUniTaskCompletionSource : IUniTaskSource, IPromisePoolItem, IPromise
+    public class AutoResetUniTaskCompletionSource : IUniTaskSource, ITaskPoolNode<AutoResetUniTaskCompletionSource>, IPromise
     {
-        static readonly PromisePool<AutoResetUniTaskCompletionSource> pool = new PromisePool<AutoResetUniTaskCompletionSource>();
+        static TaskPool<AutoResetUniTaskCompletionSource> pool;
+        public AutoResetUniTaskCompletionSource NextNode { get; set; }
+
+        static AutoResetUniTaskCompletionSource()
+        {
+            TaskPool.RegisterSizeGetter(typeof(AutoResetUniTaskCompletionSource), () => pool.Size);
+        }
 
         UniTaskCompletionSourceCore<AsyncUnit> core;
 
@@ -388,9 +394,12 @@ namespace Cysharp.Threading.Tasks
         [DebuggerHidden]
         public static AutoResetUniTaskCompletionSource Create()
         {
-            var value = pool.TryRent() ?? new AutoResetUniTaskCompletionSource();
-            TaskTracker.TrackActiveTask(value, 2);
-            return value;
+            if (!pool.TryPop(out var result))
+            {
+                result = new AutoResetUniTaskCompletionSource();
+            }
+            TaskTracker.TrackActiveTask(result, 2);
+            return result;
         }
 
         [DebuggerHidden]
@@ -452,12 +461,11 @@ namespace Cysharp.Threading.Tasks
         {
             try
             {
-                TaskTracker.RemoveTracking(this);
                 core.GetResult(token);
             }
             finally
             {
-                pool.TryReturn(this);
+                TryReturn();
             }
 
         }
@@ -481,14 +489,16 @@ namespace Cysharp.Threading.Tasks
         }
 
         [DebuggerHidden]
-        void IPromisePoolItem.Reset()
+        bool TryReturn()
         {
+            TaskTracker.RemoveTracking(this);
             core.Reset();
+            return pool.TryPush(this);
         }
 
         ~AutoResetUniTaskCompletionSource()
         {
-            if (pool.TryReturn(this))
+            if (TryReturn())
             {
                 GC.ReRegisterForFinalize(this);
                 return;
@@ -591,9 +601,15 @@ namespace Cysharp.Threading.Tasks
         }
     }
 
-    public class AutoResetUniTaskCompletionSource<T> : IUniTaskSource<T>, IPromisePoolItem, IPromise<T>
+    public class AutoResetUniTaskCompletionSource<T> : IUniTaskSource<T>, ITaskPoolNode<AutoResetUniTaskCompletionSource<T>>, IPromise<T>
     {
-        static readonly PromisePool<AutoResetUniTaskCompletionSource<T>> pool = new PromisePool<AutoResetUniTaskCompletionSource<T>>();
+        static TaskPool<AutoResetUniTaskCompletionSource<T>> pool;
+        public AutoResetUniTaskCompletionSource<T> NextNode { get; set; }
+
+        static AutoResetUniTaskCompletionSource()
+        {
+            TaskPool.RegisterSizeGetter(typeof(AutoResetUniTaskCompletionSource<T>), () => pool.Size);
+        }
 
         UniTaskCompletionSourceCore<T> core;
 
@@ -604,7 +620,10 @@ namespace Cysharp.Threading.Tasks
         [DebuggerHidden]
         public static AutoResetUniTaskCompletionSource<T> Create()
         {
-            var result = pool.TryRent() ?? new AutoResetUniTaskCompletionSource<T>();
+            if (!pool.TryPop(out var result))
+            {
+                result = new AutoResetUniTaskCompletionSource<T>();
+            }
             TaskTracker.TrackActiveTask(result, 2);
             return result;
         }
@@ -668,12 +687,11 @@ namespace Cysharp.Threading.Tasks
         {
             try
             {
-                TaskTracker.RemoveTracking(this);
                 return core.GetResult(token);
             }
             finally
             {
-                pool.TryReturn(this);
+                TryReturn();
             }
         }
 
@@ -702,14 +720,17 @@ namespace Cysharp.Threading.Tasks
         }
 
         [DebuggerHidden]
-        void IPromisePoolItem.Reset()
+        bool TryReturn()
         {
+            TaskTracker.RemoveTracking(this);
             core.Reset();
+            return pool.TryPush(this);
         }
 
+
         ~AutoResetUniTaskCompletionSource()
         {
-            if (pool.TryReturn(this))
+            if (TryReturn())
             {
                 GC.ReRegisterForFinalize(this);
             }

src/UniTask/Assets/Plugins/UniTask/Runtime/UniTaskExtensions.cs

@@ -571,7 +571,7 @@ namespace Cysharp.Threading.Tasks
 
 #if UNITY_2018_3_OR_NEWER
 
-        class ToCoroutineEnumerator : IEnumerator
+        sealed class ToCoroutineEnumerator : IEnumerator
         {
             bool completed;
             UniTask task;
@@ -629,12 +629,12 @@ namespace Cysharp.Threading.Tasks
                 return !completed;
             }
 
-            public void Reset()
+            void IEnumerator.Reset()
             {
             }
         }
 
-        class ToCoroutineEnumerator<T> : IEnumerator
+        sealed class ToCoroutineEnumerator<T> : IEnumerator
         {
             bool completed;
             Action<T> resultHandler = null;
@@ -700,11 +700,11 @@ namespace Cysharp.Threading.Tasks
                 return !completed;
             }
 
-            public void Reset()
+            void IEnumerator.Reset()
             {
             }
         }
-    
+
 #endif
     }
 }

src/UniTask/Assets/Plugins/UniTask/Runtime/UniTaskObservableExtensions.cs

@@ -9,7 +9,7 @@ namespace Cysharp.Threading.Tasks
 {
     public static class UniTaskObservableExtensions
     {
-        public static UniTask<T> ToUniTask<T>(this IObservable<T> source, CancellationToken cancellationToken = default(CancellationToken), bool useFirstValue = false)
+        public static UniTask<T> ToUniTask<T>(this IObservable<T> source, bool useFirstValue = false, CancellationToken cancellationToken = default)
         {
             var promise = new UniTaskCompletionSource<T>();
             var disposable = new SingleAssignmentDisposable();

src/UniTask/Assets/Plugins/UniTask/Runtime/UniTaskVoid.cs

@@ -9,41 +9,11 @@ using Cysharp.Threading.Tasks.CompilerServices;
 namespace Cysharp.Threading.Tasks
 {
     [AsyncMethodBuilder(typeof(AsyncUniTaskVoidMethodBuilder))]
-    public struct UniTaskVoid
+    public readonly struct UniTaskVoid
     {
         public void Forget()
         {
         }
-
-        [DebuggerHidden]
-        public Awaiter GetAwaiter()
-        {
-            return new Awaiter();
-        }
-
-        public struct Awaiter : ICriticalNotifyCompletion
-        {
-            [DebuggerHidden]
-            public bool IsCompleted => true;
-
-            [DebuggerHidden]
-            public void GetResult()
-            {
-#if UNITY_2018_3_OR_NEWER
-                UnityEngine.Debug.LogWarning("UniTaskVoid can't await, always fire-and-forget. use Forget instead of await.");
-#endif
-            }
-
-            [DebuggerHidden]
-            public void OnCompleted(Action continuation)
-            {
-            }
-
-            [DebuggerHidden]
-            public void UnsafeOnCompleted(Action continuation)
-            {
-            }
-        }
     }
 }
 

src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.Jobs.cs

@@ -9,10 +9,11 @@ namespace Cysharp.Threading.Tasks
 {
     public static partial class UnityAsyncExtensions
     {
-        public static async UniTask WaitAsync(this JobHandle jobHandle, PlayerLoopTiming waitTiming)
+        public static async UniTask WaitAsync(this JobHandle jobHandle, PlayerLoopTiming waitTiming, CancellationToken cancellationToken = default)
         {
             await UniTask.Yield(waitTiming);
             jobHandle.Complete();
+            cancellationToken.ThrowIfCancellationRequested(); // call cancel after Complete.
         }
 
         public static UniTask.Awaiter GetAwaiter(this JobHandle jobHandle)
@@ -28,7 +29,9 @@ namespace Cysharp.Threading.Tasks
 
             return new UniTask(handler, token).GetAwaiter();
         }
-     
+
+        // can not pass CancellationToken because can't handle JobHandle's Complete and NativeArray.Dispose.
+
         public static UniTask ToUniTask(this JobHandle jobHandle, PlayerLoopTiming waitTiming)
         {
             var handler = JobHandlePromise.Create(jobHandle, out var token);

src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.cs

@@ -13,7 +13,7 @@ namespace Cysharp.Threading.Tasks
 {
     public static partial class UnityAsyncExtensions
     {
-#region AsyncOperation
+        #region AsyncOperation
 
         public static AsyncOperationAwaiter GetAwaiter(this AsyncOperation asyncOperation)
         {
@@ -70,14 +70,20 @@ namespace Cysharp.Threading.Tasks
             public void UnsafeOnCompleted(Action continuation)
             {
                 Error.ThrowWhenContinuationIsAlreadyRegistered(continuationAction);
-                continuationAction = continuation.AsFuncOfT<AsyncOperation>(); // allocate delegate.
+                continuationAction = PooledDelegate<AsyncOperation>.Create(continuation);
                 asyncOperation.completed += continuationAction;
             }
         }
 
-        class AsyncOperationConfiguredSource : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        class AsyncOperationConfiguredSource : IUniTaskSource, IPlayerLoopItem, ITaskPoolNode<AsyncOperationConfiguredSource>
         {
-            static readonly PromisePool<AsyncOperationConfiguredSource> pool = new PromisePool<AsyncOperationConfiguredSource>();
+            static TaskPool<AsyncOperationConfiguredSource> pool;
+            public AsyncOperationConfiguredSource NextNode { get; set; }
+
+            static AsyncOperationConfiguredSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(AsyncOperationConfiguredSource), () => pool.Size);
+            }
 
             AsyncOperation asyncOperation;
             IProgress<float> progress;
@@ -97,7 +103,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new AsyncOperationConfiguredSource();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new AsyncOperationConfiguredSource();
+                }
 
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
@@ -115,13 +124,12 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
-                    
+
                     core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -162,26 +170,28 @@ namespace Cysharp.Threading.Tasks
                 return true;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
                 asyncOperation = default;
                 progress = default;
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~AsyncOperationConfiguredSource()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
             }
         }
 
-# endregion
+        #endregion
 
-#region ResourceRequest
+        #region ResourceRequest
 
         public static ResourceRequestAwaiter GetAwaiter(this ResourceRequest asyncOperation)
         {
@@ -242,14 +252,20 @@ namespace Cysharp.Threading.Tasks
             public void UnsafeOnCompleted(Action continuation)
             {
                 Error.ThrowWhenContinuationIsAlreadyRegistered(continuationAction);
-                continuationAction = continuation.AsFuncOfT<AsyncOperation>(); // allocate delegate.
+                continuationAction = PooledDelegate<AsyncOperation>.Create(continuation);
                 asyncOperation.completed += continuationAction;
             }
         }
 
-        class ResourceRequestConfiguredSource : IUniTaskSource<UnityEngine.Object>, IPlayerLoopItem, IPromisePoolItem
+        class ResourceRequestConfiguredSource : IUniTaskSource<UnityEngine.Object>, IPlayerLoopItem, ITaskPoolNode<ResourceRequestConfiguredSource>
         {
-            static readonly PromisePool<ResourceRequestConfiguredSource> pool = new PromisePool<ResourceRequestConfiguredSource>();
+            static TaskPool<ResourceRequestConfiguredSource> pool;
+            public ResourceRequestConfiguredSource NextNode { get; set; }
+
+            static ResourceRequestConfiguredSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(ResourceRequestConfiguredSource), () => pool.Size);
+            }
 
             ResourceRequest asyncOperation;
             IProgress<float> progress;
@@ -269,7 +285,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource<UnityEngine.Object>.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new ResourceRequestConfiguredSource();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new ResourceRequestConfiguredSource();
+                }
 
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
@@ -287,13 +306,12 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
-                    
+
                     return core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -339,26 +357,28 @@ namespace Cysharp.Threading.Tasks
                 return true;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
+                TaskTracker.RemoveTracking(this);
                 core.Reset();
                 asyncOperation = default;
                 progress = default;
                 cancellationToken = default;
+                return pool.TryPush(this);
             }
 
             ~ResourceRequestConfiguredSource()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
             }
         }
 
-# endregion
+        #endregion
 
-#region AssetBundleRequest
+        #region AssetBundleRequest
 
         public static AssetBundleRequestAwaiter GetAwaiter(this AssetBundleRequest asyncOperation)
         {
@@ -419,14 +439,20 @@ namespace Cysharp.Threading.Tasks
             public void UnsafeOnCompleted(Action continuation)
             {
                 Error.ThrowWhenContinuationIsAlreadyRegistered(continuationAction);
-                continuationAction = continuation.AsFuncOfT<AsyncOperation>(); // allocate delegate.
+                continuationAction = PooledDelegate<AsyncOperation>.Create(continuation);
                 asyncOperation.completed += continuationAction;
             }
         }
 
-        class AssetBundleRequestConfiguredSource : IUniTaskSource<UnityEngine.Object>, IPlayerLoopItem, IPromisePoolItem
+        class AssetBundleRequestConfiguredSource : IUniTaskSource<UnityEngine.Object>, IPlayerLoopItem, ITaskPoolNode<AssetBundleRequestConfiguredSource>
         {
-            static readonly PromisePool<AssetBundleRequestConfiguredSource> pool = new PromisePool<AssetBundleRequestConfiguredSource>();
+            static TaskPool<AssetBundleRequestConfiguredSource> pool;
+            public AssetBundleRequestConfiguredSource NextNode { get; set; }
+
+            static AssetBundleRequestConfiguredSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(AssetBundleRequestConfiguredSource), () => pool.Size);
+            }
 
             AssetBundleRequest asyncOperation;
             IProgress<float> progress;
@@ -446,7 +472,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource<UnityEngine.Object>.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new AssetBundleRequestConfiguredSource();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new AssetBundleRequestConfiguredSource();
+                }
 
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
@@ -464,13 +493,11 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
-                    
                     return core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -516,26 +543,28 @@ namespace Cysharp.Threading.Tasks
                 return true;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
                 core.Reset();
                 asyncOperation = default;
                 progress = default;
                 cancellationToken = default;
+                TaskTracker.RemoveTracking(this);
+                return pool.TryPush(this);
             }
 
             ~AssetBundleRequestConfiguredSource()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
             }
         }
 
-# endregion
+        #endregion
 
-#region AssetBundleCreateRequest
+        #region AssetBundleCreateRequest
 
         public static AssetBundleCreateRequestAwaiter GetAwaiter(this AssetBundleCreateRequest asyncOperation)
         {
@@ -596,14 +625,20 @@ namespace Cysharp.Threading.Tasks
             public void UnsafeOnCompleted(Action continuation)
             {
                 Error.ThrowWhenContinuationIsAlreadyRegistered(continuationAction);
-                continuationAction = continuation.AsFuncOfT<AsyncOperation>(); // allocate delegate.
+                continuationAction = PooledDelegate<AsyncOperation>.Create(continuation);
                 asyncOperation.completed += continuationAction;
             }
         }
 
-        class AssetBundleCreateRequestConfiguredSource : IUniTaskSource<AssetBundle>, IPlayerLoopItem, IPromisePoolItem
+        class AssetBundleCreateRequestConfiguredSource : IUniTaskSource<AssetBundle>, IPlayerLoopItem, ITaskPoolNode<AssetBundleCreateRequestConfiguredSource>
         {
-            static readonly PromisePool<AssetBundleCreateRequestConfiguredSource> pool = new PromisePool<AssetBundleCreateRequestConfiguredSource>();
+            static TaskPool<AssetBundleCreateRequestConfiguredSource> pool;
+            public AssetBundleCreateRequestConfiguredSource NextNode { get; set; }
+
+            static AssetBundleCreateRequestConfiguredSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(AssetBundleCreateRequestConfiguredSource), () => pool.Size);
+            }
 
             AssetBundleCreateRequest asyncOperation;
             IProgress<float> progress;
@@ -623,7 +658,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource<AssetBundle>.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new AssetBundleCreateRequestConfiguredSource();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new AssetBundleCreateRequestConfiguredSource();
+                }
 
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
@@ -641,13 +679,11 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
-                    
                     return core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -693,27 +729,29 @@ namespace Cysharp.Threading.Tasks
                 return true;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
                 core.Reset();
                 asyncOperation = default;
                 progress = default;
                 cancellationToken = default;
+                TaskTracker.RemoveTracking(this);
+                return pool.TryPush(this);
             }
 
             ~AssetBundleCreateRequestConfiguredSource()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
             }
         }
 
-# endregion
+        #endregion
 
 #if ENABLE_UNITYWEBREQUEST
-#region UnityWebRequestAsyncOperation
+        #region UnityWebRequestAsyncOperation
 
         public static UnityWebRequestAsyncOperationAwaiter GetAwaiter(this UnityWebRequestAsyncOperation asyncOperation)
         {
@@ -774,14 +812,20 @@ namespace Cysharp.Threading.Tasks
             public void UnsafeOnCompleted(Action continuation)
             {
                 Error.ThrowWhenContinuationIsAlreadyRegistered(continuationAction);
-                continuationAction = continuation.AsFuncOfT<AsyncOperation>(); // allocate delegate.
+                continuationAction = PooledDelegate<AsyncOperation>.Create(continuation);
                 asyncOperation.completed += continuationAction;
             }
         }
 
-        class UnityWebRequestAsyncOperationConfiguredSource : IUniTaskSource<UnityWebRequest>, IPlayerLoopItem, IPromisePoolItem
+        class UnityWebRequestAsyncOperationConfiguredSource : IUniTaskSource<UnityWebRequest>, IPlayerLoopItem, ITaskPoolNode<UnityWebRequestAsyncOperationConfiguredSource>
         {
-            static readonly PromisePool<UnityWebRequestAsyncOperationConfiguredSource> pool = new PromisePool<UnityWebRequestAsyncOperationConfiguredSource>();
+            static TaskPool<UnityWebRequestAsyncOperationConfiguredSource> pool;
+            public UnityWebRequestAsyncOperationConfiguredSource NextNode { get; set; }
+
+            static UnityWebRequestAsyncOperationConfiguredSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(UnityWebRequestAsyncOperationConfiguredSource), () => pool.Size);
+            }
 
             UnityWebRequestAsyncOperation asyncOperation;
             IProgress<float> progress;
@@ -801,7 +845,10 @@ namespace Cysharp.Threading.Tasks
                     return AutoResetUniTaskCompletionSource<UnityWebRequest>.CreateFromCanceled(cancellationToken, out token);
                 }
 
-                var result = pool.TryRent() ?? new UnityWebRequestAsyncOperationConfiguredSource();
+                if (!pool.TryPop(out var result))
+                {
+                    result = new UnityWebRequestAsyncOperationConfiguredSource();
+                }
 
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
@@ -819,13 +866,12 @@ namespace Cysharp.Threading.Tasks
             {
                 try
                 {
-                    TaskTracker.RemoveTracking(this);
-                    
+
                     return core.GetResult(token);
                 }
                 finally
                 {
-                    pool.TryReturn(this);
+                    TryReturn();
                 }
             }
 
@@ -853,6 +899,7 @@ namespace Cysharp.Threading.Tasks
             {
                 if (cancellationToken.IsCancellationRequested)
                 {
+                    asyncOperation.webRequest.Abort();
                     core.TrySetCanceled(cancellationToken);
                     return false;
                 }
@@ -871,24 +918,26 @@ namespace Cysharp.Threading.Tasks
                 return true;
             }
 
-            public void Reset()
+            bool TryReturn()
             {
                 core.Reset();
                 asyncOperation = default;
                 progress = default;
                 cancellationToken = default;
+                TaskTracker.RemoveTracking(this);
+                return pool.TryPush(this);
             }
 
             ~UnityWebRequestAsyncOperationConfiguredSource()
             {
-                if (pool.TryReturn(this))
+                if (TryReturn())
                 {
                     GC.ReRegisterForFinalize(this);
                 }
             }
         }
 
-# endregion
+        #endregion
 #endif
 
     }

src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.uGUI.cs

@@ -1,6 +1,5 @@
 #pragma warning disable CS1591 // Missing XML comment for publicly visible type or member
 
-using Cysharp.Threading.Tasks.Linq;
 using System;
 using System.Threading;
 using UnityEngine;

src/UniTask/Assets/Plugins/UniTask/Runtime/_InternalVisibleTo.cs

@@ -0,0 +1,3 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("UniTask.Linq")]

src/UniTask/Assets/Plugins/UniTask/Runtime/_InternalVisibleTo.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 8507e97eb606fad4b99c6edf92e19cb8
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/UniTask/Assets/Plugins/UniTask/package.json

@@ -1,8 +1,8 @@
 {
     "name": "com.cysharp.unitask",
     "displayName": "UniTask",
-    "version": "2.0.10-rc7",
-    "unity": "2018.3",
+    "version": "2.0.14",
+    "unity": "2018.4",
     "description": "Provides an efficient async/await integration to Unity.",
     "keywords": [ "async/await", "async", "Task", "UniTask" ],
     "license": "MIT",

src/UniTask/Assets/Scenes/SandboxMain.cs

@@ -1,4 +1,5 @@
 using Cysharp.Threading.Tasks;
+using System.Linq;
 using Cysharp.Threading.Tasks.Linq;
 using Cysharp.Threading.Tasks.Triggers;
 using System;
@@ -10,6 +11,8 @@ using System.Threading.Tasks;
 using Unity.Collections;
 using Unity.Jobs;
 using UnityEngine;
+using UnityEngine.LowLevel;
+using UnityEngine.Networking;
 using UnityEngine.UI;
 
 
@@ -192,15 +195,20 @@ public class SandboxMain : MonoBehaviour
     async UniTask RunJobAsync()
     {
         var job = new MyJob() { loopCount = 999, inOut = new NativeArray<int>(1, Allocator.TempJob) };
-        JobHandle.ScheduleBatchedJobs();
+        try
+        {
+            JobHandle.ScheduleBatchedJobs();
 
-        var scheduled = job.Schedule();
+            var scheduled = job.Schedule();
 
-        UnityEngine.Debug.Log("OK");
-        await scheduled; // .ConfigureAwait(PlayerLoopTiming.Update); // .WaitAsync(PlayerLoopTiming.Update);
-        UnityEngine.Debug.Log("OK2");
-
-        job.inOut.Dispose();
+            UnityEngine.Debug.Log("OK");
+            await scheduled; // .ConfigureAwait(PlayerLoopTiming.Update); // .WaitAsync(PlayerLoopTiming.Update);
+            UnityEngine.Debug.Log("OK2");
+        }
+        finally
+        {
+            job.inOut.Dispose();
+        }
     }
 
 
@@ -243,9 +251,70 @@ public class SandboxMain : MonoBehaviour
         public int MyProperty { get; set; }
     }
 
-
-    void  Start()
+    async Task Test1()
     {
+        var r = await TcsAsync("https://bing.com/");
+        Debug.Log("TASKASYNC");
+    }
+
+    async UniTaskVoid Test2()
+    {
+        try
+        {
+            //var cts = new CancellationTokenSource();
+            //var r = UniAsync("https://bing.com/", cts.Token);
+            //cts.Cancel();
+            //await r;
+            _ = await UnityWebRequest.Get("https://bing.com/").SendWebRequest();
+            Debug.Log("UNIASYNC1 ");
+
+            _ = await UnityWebRequest.Get("https://bing.com/").SendWebRequest();
+            Debug.Log("UNIASYNC2");
+        }
+        catch
+        {
+            Debug.Log("Canceled");
+        }
+    }
+
+    IEnumerator Test3(string url)
+    {
+        var req = UnityWebRequest.Get(url).SendWebRequest();
+        yield return req;
+        Debug.Log("COROUTINE");
+    }
+
+    static async Task<UnityWebRequest> TcsAsync(string url)
+    {
+        var req = await UnityWebRequest.Get(url).SendWebRequest();
+        return req;
+    }
+
+    static async UniTask<UnityWebRequest> UniAsync(string url, CancellationToken cancellationToken)
+    {
+        var req = await UnityWebRequest.Get(url).SendWebRequest().WithCancellation(cancellationToken);
+        return req;
+    }
+
+    async Task<int> Test()
+    {
+        await Task.Yield();
+        return 10;
+    }
+
+
+    void Start()
+    {
+        //_ = UniTask.Run(async () =>
+        //{
+        //    var watch = System.Diagnostics.Stopwatch.StartNew();
+        //    await UniTask.Delay(new TimeSpan(0, 0, seconds: 10));
+        //    Debug.Log(watch.Elapsed);
+        //});
+
+        //return;
+        //await UniTask.SwitchToMainThread();
+
         //UniTaskAsyncEnumerable.EveryValueChanged(mcc, x => x.MyProperty)
         //    .Do(_ => { }, () => Debug.Log("COMPLETED"))
         //    .ForEachAsync(x =>
@@ -254,53 +323,184 @@ public class SandboxMain : MonoBehaviour
         //    })
         //    .Forget();
 
+        //_ = Test1();
+        //Test2().Forget();
+        //StartCoroutine(Test3("https://bing.com/"));
+
+
+
+
+
+        //bool flip = false;
+        //var rect = cancelButton.GetComponent<RectTransform>();
+        //var cts = new CancellationTokenSource();
+        //var ct = cts.Token;
+        //okButton.onClick.AddListener(UniTask.UnityAction(async () =>
+        //{
+        //    await rect.DOMoveX(10f * (flip ? -1 : 1), 3).OnUpdate(() => { Debug.Log("UPDATE YEAH"); }).WithCancellation(ct);
+        //    flip = !flip;
+        //    // ok.
+        //}));
+        //cancelButton.onClick.AddListener(() =>
+        //{
+        //    cts.Cancel();
+        //});
 
 
         // DG.Tweening.Core.TweenerCore<int>
-        //okButton.GetComponent<RectTransform>().DOMoveX(10.2f, 30);
+        //Debug.Log("GO MOVEX");
+        //await okButton.GetComponent<RectTransform>().DOMoveX(-10.2f, 3).WithCancellation(CancellationToken.None);
+        //Debug.Log("END MOVEX");
 
 
-        // DOTween.To(
+        //Debug.Log("AGAIN MOVE");
+        //await okButton.GetComponent<RectTransform>().DOMoveY(10.2f, 3).WithCancellation(CancellationToken.None);
+        //Debug.Log("AGAIN END MOVE");
 
-        var cts = new CancellationTokenSource();
+        //Debug.Log(Test().GetType().FullName);
 
-        //var tween = okButton.GetComponent<RectTransform>().DOLocalMoveX(100, 5.0f);
 
-        cancelButton.OnClickAsAsyncEnumerable().ForEachAsync(_ =>
+
+        // check stacktrace
+        // await UniTaskAsyncEnumerable.EveryUpdate().Where((x, i) => i % 2 == 0).Select(x => x).DistinctUntilChanged().ForEachAsync(x =>
+        //{
+        // Debug.Log("test");
+        //});
+
+
+
+
+        //// DOTween.To(
+
+        //var cts = new CancellationTokenSource();
+
+        ////var tween = okButton.GetComponent<RectTransform>().DOLocalMoveX(100, 5.0f);
+
+        //cancelButton.OnClickAsAsyncEnumerable().ForEachAsync(_ =>
+        //{
+        //    cts.Cancel();
+        //}).Forget();
+
+
+        //// await tween.ToUniTask(TweenCancelBehaviour.KillAndCancelAwait, cts.Token);
+
+        ////tween.SetRecyclable(true);
+
+        //Debug.Log("END");
+
+        //// tween.Play();
+
+        //// DOTween.
+
+        //// DOVirtual.Float(0, 1, 1, x => { }).ToUniTask();
+
+
+        //await foreach (var _ in UniTaskAsyncEnumerable.EveryUpdate())
+        //{
+        //    Debug.Log("Update() " + Time.frameCount);
+        //}
+
+
+
+        //await okButton.OnClickAsAsyncEnumerable().Where((x, i) => i % 2 == 0).ForEachAsync(_ =>
+        //{
+        //});
+
+
+        //okButton.OnClickAsAsyncEnumerable().ForEachAsync(_ =>
+        //{
+
+
+        //foreach (var (type, size) in TaskPool.GetCacheSizeInfo())
+        //{
+        //    Debug.Log(type + ":" + size);
+        //}
+
+
+        //}).Forget();
+
+        //CloseAsync(this.GetCancellationTokenOnDestroy()).Forget();
+
+        //okButton.onClick.AddListener(UniTask.UnityAction(async () => await UniTask.Yield()));
+
+        PlayerLoopInfo.Inject();
+
+        //UpdateUniTask().Forget();
+
+        //StartCoroutine(Coroutine());
+
+        //await UniTask.Delay(TimeSpan.FromSeconds(1));
+
+
+        // _ = ReturnToMainThreadTest();
+
+        //GameObject.Destroy(this.gameObject);
+
+
+        SynchronizationContext.Current.Post(_ =>
         {
-            cts.Cancel();
-        }).Forget();
+            //UnityEngine.Debug.Log("Post:" + PlayerLoopInfo.CurrentLoopType);
+        }, null);
+    }
 
-
-        // await tween.ToUniTask(TweenCancelBehaviour.KillAndCancelAwait, cts.Token);
-
-        //tween.SetRecyclable(true);
-
-        Debug.Log("END");
-
-        // tween.Play();
-
-        // DOTween.
-
-        // DOVirtual.Float(0, 1, 1, x => { }).ToUniTask();
-
-        okButton.OnClickAsAsyncEnumerable().ForEachAsync(_ =>
+    async UniTaskVoid UpdateUniTask()
+    {
+        while (true)
         {
+            await UniTask.Yield();
+            UnityEngine.Debug.Log("UniTaskYield:" + PlayerLoopInfo.CurrentLoopType);
+        }
+    }
 
 
+    async UniTaskVoid ReturnToMainThreadTest()
+    {
+        var d = UniTask.ReturnToCurrentSynchronizationContext();
+        try
+        {
+            UnityEngine.Debug.Log("In MainThread?" + Thread.CurrentThread.ManagedThreadId);
+            UnityEngine.Debug.Log("SyncContext is null?" + (SynchronizationContext.Current == null));
+            await UniTask.SwitchToThreadPool();
+            UnityEngine.Debug.Log("In ThreadPool?" + Thread.CurrentThread.ManagedThreadId);
+            UnityEngine.Debug.Log("SyncContext is null?" + (SynchronizationContext.Current == null));
+        }
+        finally
+        {
+            await d.DisposeAsync();
+        }
+
+        UnityEngine.Debug.Log("In ThreadPool?" + Thread.CurrentThread.ManagedThreadId);
+        UnityEngine.Debug.Log("SyncContext is null2" + (SynchronizationContext.Current == null));
+    }
 
 
+    private void Update()
+    {
+        // UnityEngine.Debug.Log("Update:" + PlayerLoopInfo.CurrentLoopType);
+    }
 
-        }).Forget();
-
-
-
-        okButton.onClick.AddListener(UniTask.UnityAction(async () => await UniTask.Yield()));
+    IEnumerator Coroutine()
+    {
+        try
+        {
+            while (true)
+            {
+                yield return null;
+                //UnityEngine.Debug.Log("Coroutine null:" + PlayerLoopInfo.CurrentLoopType);
+            }
+        }
+        finally
+        {
+            UnityEngine.Debug.Log("Coroutine Finally");
+        }
     }
 
     async UniTaskVoid CloseAsync(CancellationToken cancellationToken = default)
     {
-        await UniTask.Yield();
+        while (true)
+        {
+            await UniTask.Yield(PlayerLoopTiming.Update, cancellationToken);
+        }
     }
 
     async UniTaskVoid Running(CancellationToken ct)
@@ -533,7 +733,7 @@ public class SandboxMain : MonoBehaviour
     }
 }
 
-public class ShowPlayerLoop
+public class PlayerLoopInfo
 {
     // [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
     static void Init()
@@ -564,4 +764,45 @@ public class ShowPlayerLoop
 
         UnityEngine.Debug.Log(sb.ToString());
     }
+
+    public static Type CurrentLoopType { get; private set; }
+
+    public static void Inject()
+    {
+        var system = PlayerLoop.GetCurrentPlayerLoop();
+
+        for (int i = 0; i < system.subSystemList.Length; i++)
+        {
+            var loop = system.subSystemList[i].subSystemList.SelectMany(x =>
+            {
+                var t = typeof(WrapLoop<>).MakeGenericType(x.type);
+                var instance = (ILoopRunner)Activator.CreateInstance(t, x.type);
+                return new[] { new PlayerLoopSystem { type = t, updateDelegate = instance.Run }, x };
+            }).ToArray();
+
+            system.subSystemList[i].subSystemList = loop;
+        }
+
+        PlayerLoop.SetPlayerLoop(system);
+    }
+
+    interface ILoopRunner
+    {
+        void Run();
+    }
+
+    class WrapLoop<T> : ILoopRunner
+    {
+        readonly Type type;
+
+        public WrapLoop(Type type)
+        {
+            this.type = type;
+        }
+
+        public void Run()
+        {
+            CurrentLoopType = type;
+        }
+    }
 }

src/UniTask/Assets/Tests/GenericsWhenAllAny.cs

@@ -0,0 +1,165 @@
+#if CSHARP_7_OR_LATER || (UNITY_2018_3_OR_NEWER && (NET_STANDARD_2_0 || NET_4_6))
+#pragma warning disable CS1591 // Missing XML comment for publicly visible type or member
+
+using UnityEngine;
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using UnityEngine.UI;
+using UnityEngine.Scripting;
+using Cysharp.Threading.Tasks;
+using Unity.Collections;
+using System.Threading;
+using NUnit.Framework;
+using UnityEngine.TestTools;
+using FluentAssertions;
+
+namespace Cysharp.Threading.TasksTests
+{
+    public class GenericsWhenAllAny
+    {
+
+        [UnityTest]
+        public IEnumerator WhenAllT15() => UniTask.ToCoroutine(async () =>
+        {
+            var t01 = Tes<int>();
+            var t02 = Tes<int>();
+            var t03 = Tes<int>();
+            var t04 = Tes<int>();
+            var t05 = Tes<int>();
+            var t06 = Tes<int>();
+            var t07 = Tes<int>();
+            var t08 = Tes<int>();
+            var t09 = Tes<int>();
+            var t10 = Tes<int>();
+            var t11 = Tes<int>();
+            var t12 = Tes<int>();
+            var t13 = Tes<int>();
+            var t14 = Tes<int>();
+            var t15 = Tes<int>();
+
+            await UniTask.WhenAll(t01, t02, t03, t04, t05, t06, t07, t08, t09, t10, t11, t12, t13, t14, t15);
+        });
+
+        [UnityTest]
+        public IEnumerator WhenAllT01_Generics1() => UniTask.ToCoroutine(async () =>
+        {
+            var t01 = Tes<MyGenerics<int>>();
+
+            await UniTask.WhenAll(t01);
+        });
+
+        [UnityTest]
+        public IEnumerator WhenAllT02_Generics1() => UniTask.ToCoroutine(async () =>
+        {
+            var t01 = Tes<MyGenerics<int>>();
+            var t02 = Tes<MyGenerics<int>>();
+
+            await UniTask.WhenAll(t01, t02);
+        });
+
+        [UnityTest]
+        public IEnumerator WhenAllT03_Generics1() => UniTask.ToCoroutine(async () =>
+        {
+            var t01 = Tes<MyGenerics<int>>();
+            var t02 = Tes<MyGenerics<int>>();
+            var t03 = Tes<MyGenerics<int>>();
+
+            await UniTask.WhenAll(t01, t02, t03);
+        });
+
+        [UnityTest]
+        public IEnumerator WhenAllT04_Generics1() => UniTask.ToCoroutine(async () =>
+        {
+            var t01 = Tes<MyGenerics<int>>();
+            var t02 = Tes<MyGenerics<int>>();
+            var t03 = Tes<MyGenerics<int>>();
+            var t04 = Tes<MyGenerics<int>>();
+
+            await UniTask.WhenAll(t01, t02, t03, t04);
+        });
+
+        // will fail.
+
+        //[UnityTest]
+        //public IEnumerator WhenAllT05_Generics1() => UniTask.ToCoroutine(async () =>
+        //{
+        //    var t01 = Tes<MyGenerics<int>>();
+        //    var t02 = Tes<MyGenerics<int>>();
+        //    var t03 = Tes<MyGenerics<int>>();
+        //    var t04 = Tes<MyGenerics<int>>();
+        //    var t05 = Tes<MyGenerics<int>>();
+
+        //    await UniTask.WhenAll(t01, t02, t03, t04, t05);
+        //});
+
+        //[UnityTest]
+        //public IEnumerator WhenAllT06_Generics1() => UniTask.ToCoroutine(async () =>
+        //{
+        //    var t01 = Tes<MyGenerics<int>>();
+        //    var t02 = Tes<MyGenerics<int>>();
+        //    var t03 = Tes<MyGenerics<int>>();
+        //    var t04 = Tes<MyGenerics<int>>();
+        //    var t05 = Tes<MyGenerics<int>>();
+        //    var t06 = Tes<MyGenerics<int>>();
+
+        //    await UniTask.WhenAll(t01, t02, t03, t04, t05, t06);
+        //});
+
+        //[UnityTest]
+        //public IEnumerator WhenAllT07_Generics1() => UniTask.ToCoroutine(async () =>
+        //{
+        //    var t01 = Tes<MyGenerics<int>>();
+        //    var t02 = Tes<MyGenerics<int>>();
+        //    var t03 = Tes<MyGenerics<int>>();
+        //    var t04 = Tes<MyGenerics<int>>();
+        //    var t05 = Tes<MyGenerics<int>>();
+        //    var t06 = Tes<MyGenerics<int>>();
+        //    var t07 = Tes<MyGenerics<int>>();
+
+        //    await UniTask.WhenAll(t01, t02, t03, t04, t05, t06, t07);
+        //});
+
+        //[UnityTest]
+        //public IEnumerator WhenAllT15_Generics1() => UniTask.ToCoroutine(async () =>
+        //{
+        //    var t01 = Tes<MyGenerics<int>>();
+        //    var t02 = Tes<MyGenerics<int>>();
+        //    var t03 = Tes<MyGenerics<int>>();
+        //    var t04 = Tes<MyGenerics<int>>();
+        //    var t05 = Tes<MyGenerics<int>>();
+        //    var t06 = Tes<MyGenerics<int>>();
+        //    var t07 = Tes<MyGenerics<int>>();
+        //    var t08 = Tes<MyGenerics<int>>();
+        //    var t09 = Tes<MyGenerics<int>>();
+        //    var t10 = Tes<MyGenerics<int>>();
+        //    var t11 = Tes<MyGenerics<int>>();
+        //    var t12 = Tes<MyGenerics<int>>();
+        //    var t13 = Tes<MyGenerics<int>>();
+        //    var t14 = Tes<MyGenerics<int>>();
+        //    var t15 = Tes<MyGenerics<int>>();
+
+        //    await UniTask.WhenAll(t01, t02, t03, t04, t05, t06, t07, t08, t09, t10, t11, t12, t13, t14, t15);
+        //});
+
+        async UniTask<T> Tes<T>()
+        {
+            await UniTask.Yield();
+            return default;
+        }
+    }
+
+    public class MyGenerics<T>
+    {
+
+    }
+
+    public class MyGenerics2
+    {
+
+    }
+}
+
+#endif

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