How to set backpressure on dart stream. (or rxDart)

Is there a way to set backpressure on a dart stream?

I want to implement a function like this:

1. The user presses a button.
2. Add data to PublishSubject.
3. Even if other data is added while the added data is being processed, it is ignored.

I don't know how to this it.

Any good way?

Dart Stream has built-in backpressure (buffered).

Stream.periodic(const Duration(milliseconds: 100), (i) => i)
  .take(5)
  .listen((v) async {
    await Future<void>.delayed(const Duration(milliseconds: 500));
    print(v);
  });

await Future<void>.delayed(const Duration(seconds: 10));

// will print 0, 1, 2, 3, 4

You can use exhaustMap of rxdart to ignore/drop values.

Stream.periodic(const Duration(milliseconds: 100), (i) => i)
  .take(5)
  .exhaustMap((v) => Rx.timer(v, const Duration(milliseconds: 500)))
  .listen(print);

await Future<void>.delayed(const Duration(seconds: 10));

// will print 0