using correct code to disconnect from WS (#667)

Author: Brazol

packages/stream_video/lib/src/call/session/call_session.dart

@@ -32,6 +32,7 @@ import '../../webrtc/peer_connection.dart';
 import '../../webrtc/rtc_manager.dart';
 import '../../webrtc/rtc_manager_factory.dart';
 import '../../webrtc/sdp/editor/sdp_editor.dart';
+import '../../ws/ws.dart';
 import '../state/call_state_notifier.dart';
 import 'call_session_config.dart';
 
@@ -256,7 +257,9 @@ class CallSession extends Disposable {
     _eventsSubscription = null;
     await _statsSubscription?.cancel();
     _statsSubscription = null;
-    await sfuWS.disconnect();
+    await sfuWS.disconnect(
+      StreamWebSocketCloseCode.closeSocketFromClient.value,
+    );
     await rtcManager?.dispose();
     rtcManager = null;
     _peerConnectionCheckTimer?.cancel();

packages/stream_video/lib/src/webrtc/peer_connection.dart

@@ -277,6 +277,7 @@ class StreamPeerConnection extends Disposable {
       ..onAddStream = null
       ..onRemoveStream = null
       ..onAddTrack = null
+      ..onTrack = null
       ..onRemoveTrack = null
       ..onIceCandidate = null
       ..onIceConnectionState = null

packages/stream_video/lib/src/ws/ws.dart

@@ -13,6 +13,13 @@ import 'connect/connect.dart'
 
 export 'package:web_socket_channel/web_socket_channel.dart';
 
+enum StreamWebSocketCloseCode {
+  closeSocketFromClient(1000);
+
+  const StreamWebSocketCloseCode(this.value);
+  final int value;
+}
+
 /// A simple wrapper around [WebSocketChannel] to make it easier to use.
 abstract class StreamWebSocket {
   /// Creates a new instance of [StreamWebSocket].