public void ConcatAll_must_work_together_with_SplitWhen()
{
var subscriber = TestSubscriber.CreateProbe<int>(this);
var source = Source.From(Enumerable.Range(1, 10))
.SplitWhen(x => x%2 == 0)
.PrefixAndTail(0)
.Select(x => x.Item2)
.ConcatSubstream()
.ConcatMany(x => x);
((Source<int, NotUsed>) source).RunWith(Sink.FromSubscriber(subscriber), Materializer);
for (var i = 1; i <= 10; i++)
subscriber.RequestNext(i);
subscriber.Request(1);
subscriber.ExpectComplete();}