disconnect method

Implementation

@override
Future<void> disconnect() async {
  final SshTransportStream? transportStream = _transportStream;
  final Socket? socket = _socket;

  _transportStream = null;
  _socket = null;
  _handshake = null;
  _state = SshTransportState.closed;

  if (transportStream != null) {
    await transportStream.close();
    return;
  }

  if (socket != null) {
    await socket.close();
    socket.destroy();
  }
}