onListen method

@override List<StreamSubscription> onListen()

Implement stream subscription

Implementation

@override
List<StreamSubscription> onListen() {
  final webSocket = client;
  if (webSocket == null) {
    throw StateError('webSocket is null');
  }

  return [
    webSocket.onClose.listen((e) {
      MqttLogger.log(
          'MqttBrowserConnection::_startListening - websocket is closed');
      onDone();
    }),
    webSocket.onMessage.listen((MessageEvent e) {
      onData(e.data);
    }),
    webSocket.onError.listen((e) {
      MqttLogger.log(
          'MqttBrowserConnection::_startListening - websocket has errored');
      onError(e);
    }),
  ];
}