handle canceling of streamSubscriptions in websocket_client for Conne…

…ctionState stream

packages/ndk/lib/data_layer/repositories/nostr_transport/websocket_client_nostr_transport.dart

@@ -14,14 +14,15 @@ import '../../data_sources/websocket_client.dart';
 class WebSocketClientNostrTransport implements NostrTransport {
   /// The underlying WebSocket data source.
   final WebsocketDSClient _websocketDS;
+  late StreamSubscription<ConnectionState> _stateStreamSubscription;
 
   /// Creates a new WebSocketNostrTransport instance.
   ///
   /// [_websocketDS] is the WebSocket data source to be used for communication.
   WebSocketClientNostrTransport(this._websocketDS, [Function? onReconnect]) {
     Completer completer = Completer();
     ready = completer.future;
-    _websocketDS.ws.connection.listen((state) {
+    _stateStreamSubscription = _websocketDS.ws.connection.listen((state) {
       Logger.log.t("${_websocketDS.url} connection state changed to $state");
       switch (state) {
         case Connected() || Reconnected():
@@ -45,6 +46,7 @@ class WebSocketClientNostrTransport implements NostrTransport {
   /// Returns a Future that completes when the connection has been closed.
   @override
   Future<void> close() async {
+    await _stateStreamSubscription.cancel();
     return _websocketDS.close();
   }
 

packages/ndk/lib/domain_layer/entities/relay_connectivity.dart

@@ -35,11 +35,11 @@ class RelayConnectivity<T> {
   /// cancels stream subscription and closes relay transport
   Future<void> close() async {
     if (_streamSubscription != null) {
-      _streamSubscription!.cancel();
+      await _streamSubscription!.cancel();
     }
     if (relayTransport != null && relayTransport!.isOpen()) {
       Logger.log.t("closing $url webSocket");
-      relayTransport!
+      await relayTransport!
           .close()
           .timeout(const Duration(seconds: 3), onTimeout: () {
         Logger.log.w("timeout while trying to close socket $url");