code: private void closeConnection(WsOutbound outbound, int guacamoleStatusCode,
              int webSocketCode) {
  
          try {
              byte[] message = Integer.toString(guacamoleStatusCode).getBytes("UTF-8");
              outbound.close(webSocketCode, ByteBuffer.wrap(message));
          }
          catch (IOException e) {
              logger.debug("Unable to close WebSocket tunnel.", e);
          }
  
      }
docs: Sends the given Guacamole and WebSocket numeric status
  on the given WebSocket connection and closes the
  connection.
  
  @param outbound
  The outbound WebSocket connection to close.
  
  @param guacamoleStatusCode
  The status to send.
  
  @param webSocketCode
  The numeric WebSocket status code to send.