release method

@override void release()

Implementation

@override
void release() {
  _callback = null;
  _abaPosSdkFlutterPlugin = null;
  _plugin = null;
  _unregisterUsbAttachedOrDetachedEvent();
  _cancelTimer();
  _cancelReadSerialPortDataSubscription();
  _closeSerialPort();
  super.release();
}