fix message repeat error

AwesomeUIWidgets/Assets/Scripts/ChatPage.cs

     {
         public readonly ChatComponents.User _user = new ChatComponents.User("06c33e8b-e835-4736-80f4-63f44b66666c");
         private List<ChatComponents.Message> _messages = new List<ChatComponents.Message>();
+        private List<ChatComponents.Message> init_messages = new List<ChatComponents.Message>();
+        private bool isReached = false;
 
         public override void initState()
         {
 
-        private void _addMessage(ChatComponents.Message message)
+        private void _addMessage(int index, ChatComponents.Message message)
-                _messages.Insert(0, message);
+                _messages.Insert(index, message);
             });
         }
 
                 text: message.text
             );
 
-            _addMessage(textMessage);
+            _addMessage(0, textMessage);
-        private Future _handleEndReached()
-        {
-            setState(()=> {
-                {
-                    _messages.AddRange(_messages);
-                    _page = _page + 1;
-                }
-            });
-            return Future.value();
-        }
-        private void _loadMessages()
+
+        public List<ChatComponents.Message> InitMessages()
         {
             List<ChatComponents.Message> results = new List<ChatComponents.Message>();
             TextAsset info = Resources.Load<TextAsset>("assets/messages");
                         status: ChatRoomUtils.getStatusFromString(_message.status),
                         text: _message.text
                     )
-                    );
+                );
-         
+
+            return results;
+        }
+
+
+        private Future _handleEndReached()
+        {
+            if (!isReached)
+            {
+                isReached = true;
+                if (init_messages.isEmpty())
+                {
+                    init_messages = InitMessages();
+                }
+                return Future.delayed(TimeSpan.FromMilliseconds(1000), () =>
+                {
+                    foreach (var message in init_messages)
+                    {
+                        _addMessage(_messages.Count, message);
+                    }
+                    _page = _page + 1;
+                    isReached = false;
+                    return Future.value();
+                });
+            }
+            else
+            {
+                return Future.value();
+            }
+            
+        }
+        private void _loadMessages()
+        {
+            List<ChatComponents.Message> results = InitMessages();
             setState(() => { _messages = results; });
         }