Feature request: Flattening StreamQueue about async HOT 6 OPEN

CombinedIterableView is slightly more performant (~6% using JIT) than expand((e) => e).

Also, stream.expand has a slightly different behavior than the snippet above: it adds all elements of the inner iterable to the event sink without waiting:
https://github.com/dart-lang/sdk/blob/44316eaadef1150b2e9d5375f30fba8004a468aa/sdk/lib/async/stream_pipe.dart#L248-L252

from async.

Having a method which flattens a Stream<List<T>> into a Stream<T> would be fine, but embedding it into StreamQueue would probably not be worth it. The use case is too specialized for the functionality to carry its own weight.

from async.

Interestingly, we can actually have both of:

extension X1<T> on Stream<Stream<T>> {
  Stream<T> flatten() async* {
    await for (var s in this) yield* s;
  }
}
extension X2<T> on Stream<Iterable<T>> {
  Stream<T> flatten() async* {
    await for (var it in this) for (var e in it) yield e;
  }
}

Can't do that with instance methods!

from async.

final byteQueue = StreamQueue(chunkStream.expand((l) =>l));

Similarly CombinedIterableView can be replaced with iterable.expand((e) => e). I'm not sure how much value it buys to name these concepts...

from async.

Makes sense. I think we could accept a PR for this.

from async.

We added Iterable<T> get flattened for iterables. An extension in this package for Stream<T> get flattened would be a good addition.

from async.