[optimize] optimize interact and performance

Runtime/Coord/Polar/PolarCoordContext.cs

@@ -10,12 +10,12 @@ namespace XCharts.Runtime
         /// the center position of polar in container.
         /// |极坐标在容器中的具体中心点。
         /// </summary>
-        public Vector3 center { get; internal set; }
+        public Vector3 center;
         /// <summary>
         /// the true radius of polar.
         /// |极坐标的运行时实际半径。
         /// </summary>
-        public float radius { get; internal set; }
-        public bool isPointerEnter { get; set; }
+        public float radius;
+        public bool isPointerEnter;
     }
 }