void main() async {
  final stream = fn();

  print('here');
  print(await stream.first);
  print('done');
}

Stream<int> fn() async* {
  print('try');
  try {
    while (true) {
      print('send message');
      yield 1;
      await Future.delayed(Duration(seconds: 1));
    }
  } finally {
    print('end');
  }
}