public void A_Flow_with_SelectAsync_must_handle_cancel_properly()
{
this.AssertAllStagesStopped(() =>
{
var pub = TestPublisher.CreateManualProbe<int>(this);
var sub = TestSubscriber.CreateManualProbe<int>(this);
Source.FromPublisher(pub)
.SelectAsync(4, _ => Task.FromResult(0))
.RunWith(Sink.FromSubscriber(sub), Materializer);
var upstream = pub.ExpectSubscription();
upstream.ExpectRequest();
sub.ExpectSubscription().Cancel();
upstream.ExpectCancellation();
}, Materializer);
}