code: protected void fireEvent(SerialPortEventTypes eventType) {
          executor.submit(new Runnable() {
              @Override
              public void run() {
                  for (SerialPortEventListener listener : eventListeners) {
                      listener.serialEvent(new SerialPortEvent(eventType));
                  }
  
              }
          });
      }
docs: Tell the client if there is data available, etc.