fetchCowData method Null safety

Future<void> fetchCowData()

소 데이터를 가져옴

Implementation

Future<void> fetchCowData() async {
  _fetchCowDataSub?.pause();
  _fetchCowDataSub?.cancel();

  _fetchCowDataSub = _fetchCowData().asStream().listen(fetchCowDataListener, cancelOnError: true);
}