Old socket listeners not destroyed when I connect a new socket with previous ip and port

[sdjalft]

PinusSocketioClient(
      ip,
      13100,
      onConnect: (client) {
        client.request([
          apiMap.GATE_getTargetConnector,
          ({
            'roomId': roomId,
          } as Map<String, dynamic>),
          (data) {
            client.disconnect();
            completer.complete((port: data['port']) as ({
              int port
            }));
          }
        ]);
      },
      onError: (err, client) {
        Toast.show('error：$err');
        client.disconnect();
        if (!completer.isCompleted) {
          completer.complete((port: 0));
        }
      },
      onDisconnect: (client) {
        client.disconnect();
        if (!completer.isCompleted) {
          completer.complete((port: 0));
        }
      },
    );

here is my socket client code. and when socket error, I try to create a new Socket like this.

when socket error again, the onError Event called twice. The first time that event called,client's hashCode equals destroyed client's hashcode.

Here is my dispose code:

void disconnect() {
    _socket.disconnect();
    _socket.dispose();
    _socket.close();
  }