shutdown method

@override Future<void> shutdown()

Implementation

@override
Future<void> shutdown() async {
  if (_backgroundCallbacksRegistered) {
    await _methodChannel.invokeMethod<void>('unregisterBackgroundCallback');
    _backgroundCallbacksRegistered = false;
  }
  await _methodChannel.invokeMethod<void>('shutdown');
  _backgroundCallback = null;
  final messenger = _tryResolveBinaryMessenger();
  if (messenger != null) {
    messenger.setMessageHandler('simple_native_timer/background', null);
  }
}