Average, MinMax, and others

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

@@ -0,0 +1,55 @@
+using System;
+using System.Runtime.CompilerServices;
+using System.Threading;
+
+namespace Cysharp.Threading.Tasks
+{
+    public partial struct UniTask
+    {
+        public static UniTask.YieldAwaitable Yield()
+        {
+            return default;
+        }
+
+        public readonly struct YieldAwaitable
+        {
+            public Awaiter GetAwaiter()
+            {
+                return default;
+            }
+
+            public readonly struct Awaiter : ICriticalNotifyCompletion
+            {
+                static readonly SendOrPostCallback SendOrPostCallbackDelegate = Continuation;
+                static readonly WaitCallback WaitCallbackDelegate = Continuation;
+
+                public bool IsCompleted => false;
+
+                public void GetResult() { }
+
+                public void OnCompleted(Action continuation)
+                {
+                    UnsafeOnCompleted(continuation);
+                }
+
+                public void UnsafeOnCompleted(Action continuation)
+                {
+                    var syncContext = SynchronizationContext.Current;
+                    if (syncContext != null)
+                    {
+                        syncContext.Post(SendOrPostCallbackDelegate, continuation);
+                    }
+                    else
+                    {
+                        ThreadPool.UnsafeQueueUserWorkItem(WaitCallbackDelegate, continuation);
+                    }
+                }
+
+                static void Continuation(object state)
+                {
+                    ((Action)state).Invoke();
+                }
+            }
+        }
+    }
+}