int idx = 0;
Future<int> getValueExceptionOnEnd() async {
  if (idx < 4) {
    return idx++;
  } else {
    throw RangeError("no more ints for you!");
  }
}

Stream<int> onlyWorksOnDesktop() async* {
  try {
    while (true) {
      yield await getValueExceptionOnEnd();
    }
  } on RangeError {
    print("all done! dart should close the stream after this.");
    return;
  }
}

Future<int?> _allPlatformsHelper() async {
  try {
    return await getValueExceptionOnEnd();
  } on RangeError {
    return null;
  }
}

Stream<int> worksOnAllPlatforms() async* {
  while (true) {
    final value = await _allPlatformsHelper();
    if (value == null) break;
    yield value;
  }
  print("all done! dart should close the stream after this.");
}

void bugDemo() async {
  idx = 0;
  await for (var value in worksOnAllPlatforms()) {
    print(value);
  }
  print("worksOnAllPlatforms()'s stream closed.");

  idx = 0;
  await for (var value in onlyWorksOnDesktop()) {
    print(value);
  }
  //This never runs when developing for the web with flutter
  //(though, interestingly, it does work with dart2js.)
  print("onlyWorksOnDesktop()'s stream closed.");
}