Merge pull request #127 from Unity-Technologies/siyaoH/1.17/android

channel message

com.unity.uiwidgets/Runtime/engine/UIWidgetsMessageManager.cs

 using System.Collections.Generic;
-using System.Runtime.InteropServices;
+using Unity.UIWidgets.engine2;
+using Unity.UIWidgets.service;
+using Unity.UIWidgets.ui;
 using UnityEngine;
 
 namespace Unity.UIWidgets.engine {
             }  
         }
 
-        Queue<string> messages = new Queue<string>();
-
-            messages.Enqueue(message);
-        }
-
-        public void handlePlatformMessage(){
-            while (!messages.isEmpty()) {
-
-                var message = messages.Dequeue();
+            using (Isolate.getScope(TextInput._currentConnection.isolate)) {
                 JSONObject jsonObject = (JSONObject) JSON.Parse(message);
                 string channel = jsonObject["channel"].Value;
                 string method = jsonObject["method"].Value;

com.unity.uiwidgets/Runtime/services/keyboard.cs

                 return;
             }
 
-            var isolate = Isolate.current;
+            var isolate = TextInput._currentConnection.isolate;
             using (Isolate.getScope(isolate)) {
                 switch (method) {
                     case "TextInputClient.updateEditingState":

com.unity.uiwidgets/Runtime/services/text_input.cs

             _client = client;
             _id = _nextId++;
         }
+
+        public Isolate isolate {
+            get { return _window._panel.isolate; }
+        }
         
         internal Size _cachedSize;
         internal Matrix4 _cachedTransform;

com.unity.uiwidgets/Runtime/ui2/hooks.cs

         [MonoPInvokeCallback(typeof(Window_drawFrameCallback))]
         static void Window_drawFrame() {
             try {
-#if !UNITY_EDITOR && (UNITY_ANDROID || UNITY_IOS)
-                UIWidgetsMessageManager.instance.handlePlatformMessage();
-#endif
                 Window.instance.onDrawFrame?.Invoke();
             }
             catch (Exception ex) {