diff --git a/lib/socket/protobuf_client.dart b/lib/socket/protobuf_client.dart
index 7630d81..b845243 100644
--- a/lib/socket/protobuf_client.dart
+++ b/lib/socket/protobuf_client.dart
@@ -13,10 +13,10 @@ import 'package:dart_framework/socket/packets/message_common.pb.dart';
 abstract class ProtobufClient extends Communicator
 {
   final int _headerSize = 4;
-  final int _heartbeatIntervalTime;
-  final int _heartbeatWaitTime;
+  late int _heartbeatIntervalTime;
+  late int _heartbeatWaitTime;
   final Socket _socket;
-  late ResponseChecker? _heartbeatChecker;
+  late ResponseChecker? _heartbeatChecker = null;
   int? _length = null;
   bool _isAlive = false;
   late List<int> _arrivedData = [];
@@ -31,25 +31,32 @@ abstract class ProtobufClient extends Communicator
       (HeartBeat).toString() : HeartBeat.fromBuffer
     });
     super.initialize(parserMap);
-    addListener(onHeartBeat);
     _socket.listen(onData, onError: onError)
             .asFuture().then(onDisconnected);
+    addListener(onHeartBeat);
     sendHeartBeat();
   }
 
   void sendHeartBeat() {
-    _heartbeatChecker?.responsed();
-    _heartbeatChecker = ResponseChecker.seecond(this, _heartbeatIntervalTime, (client) {
-      send(HeartBeat());
-      _heartbeatChecker = ResponseChecker.seecond(this, _heartbeatWaitTime, (client) {
-        dispose();
-        onDisconnected(null);
+    if(_isAlive) {
+      _heartbeatChecker?.responsed();
+      _heartbeatChecker = ResponseChecker.second(this, _heartbeatIntervalTime, (client) {
+        if(_isAlive) {
+          print('=== sendHartBeat');
+          send(HeartBeat());
+          _heartbeatChecker = ResponseChecker.second(this, _heartbeatWaitTime, (client) {
+            if(_isAlive) {
+              dispose();
+              onDisconnected(null);
+            }
+          });
+        }
       });
-    });
+    }
   }
 
   void onHeartBeat(HeartBeat data) {
-    sendHeartBeat();
+    print('=== onHeartBeat');
   }
 
   void addDisconnectListener(void Function(ProtobufClient) handler) {
@@ -68,10 +75,13 @@ abstract class ProtobufClient extends Communicator
 
   void onDisconnected(dynamic data) {
     //client disconnected
-    for (var item in _onDisconnectListenerList) {
-      item.call(this);
+    if(_isAlive)
+    {
+      for (var item in _onDisconnectListenerList) {
+        item.call(this);
+      }
+      _onDisconnectListenerList.clear();
     }
-    _onDisconnectListenerList.clear();
   }
 
   void onError(dynamic e) {
@@ -81,7 +91,6 @@ abstract class ProtobufClient extends Communicator
   void onData(Uint8List data) async {
     try
     {
-      sendHeartBeat();
       // printPacket('## Received', data);
       if(_length == null)
       {
@@ -101,6 +110,8 @@ abstract class ProtobufClient extends Communicator
         onReceivedData(common.typeName, common.data);
         _length = null;
         _arrivedData.clear();
+
+        sendHeartBeat();
       }
     } on Exception catch(e) {
       print(e);
@@ -109,22 +120,28 @@ abstract class ProtobufClient extends Communicator
 
   @override
   Future send<T extends GeneratedMessage>(T data) async {
-    List<int> packet = [];
-    var base = PacketBase();
-    base.typeName = data.info_.qualifiedMessageName;
-    base.nonce = 0;
-    base.data = data.writeToBuffer();
-    var baseBytes = base.writeToBuffer();
-    int length = baseBytes.length + _headerSize;
-    var header = Uint8List(_headerSize)
-                  ..buffer.asByteData().setInt32(0, length);
-    packet.addAll(header);
-    packet.addAll(baseBytes);
+    if(_isAlive) {
+      try {
+        List<int> packet = [];
+        var base = PacketBase();
+        base.typeName = data.info_.qualifiedMessageName;
+        base.nonce = 0;
+        base.data = data.writeToBuffer();
+        var baseBytes = base.writeToBuffer();
+        int length = baseBytes.length + _headerSize;
+        var header = Uint8List(_headerSize)
+                      ..buffer.asByteData().setInt32(0, length);
+        packet.addAll(header);
+        packet.addAll(baseBytes);
 
-    // printPacket('Send', packet);
+        // printPacket('Send', packet);
 
-    _socket.add(packet);
-    await _socket.flush();
+        _socket.add(packet);
+        await _socket.flush();
+      } catch(e, s) {
+        onDisconnected(null);
+      }
+    }
     return simpleFuture;
   }
 
@@ -142,27 +159,37 @@ abstract class ProtobufClient extends Communicator
     {
       _isAlive = false;
       _heartbeatChecker?.responsed();
-      await _socket.close();
-      _socket.destroy();
+      try {
+        await _socket.close();
+        _socket.destroy();
+      } catch (e, s) {}
     }
   }
 }
 
 class ResponseChecker<T> {
   final T _responser;
-  late Timer _timer;
-  ResponseChecker(this._responser, int time, void Function(T) notResponseListener) {
-    _timer = Timer(Duration(milliseconds: time), () {
-      notResponseListener(_responser);
+  late int _time;
+  late Timer? _timer = null;
+  late void Function(T) _notResponseListener;
+  ResponseChecker(this._responser, this._time, this._notResponseListener) {
+    startTimer();
+  }
+
+  ResponseChecker.second(this._responser, int time, this._notResponseListener) {
+    this._time = time * 1000;
+    startTimer();
+  }
+
+  void startTimer() {
+    _timer = Timer(Duration(milliseconds: _time), () {
+      _notResponseListener(_responser);
     });
   }
 
-  ResponseChecker.seecond(this._responser, int time, void Function(T) notResponseListener) {
-    ResponseChecker(this._responser, time * 1000, notResponseListener);
-  }
-
   T responsed() {
-    _timer.cancel();
+    _timer?.cancel();
+    _timer = null;
     return _responser;
   }
 }
\ No newline at end of file
diff --git a/lib/socket/protobuf_server.dart b/lib/socket/protobuf_server.dart
index 220ec5d..0add61b 100644
--- a/lib/socket/protobuf_server.dart
+++ b/lib/socket/protobuf_server.dart
@@ -34,7 +34,6 @@ abstract class ProtobufServer
 
   void onDisconnectedClient(ProtobufClient client)
   {
-    client.removeDisconnectListener(onDisconnectedClient);
     _clientList.remove(client);
     client.dispose();
     print('Client disconnected');