Akka.Streams.Tests.Dsl.FlowGroupBySpec.GroupBy_must_work_in_the_happy_case C# (CSharp) Method

        public void GroupBy_must_work_in_the_happy_case()
        {
            this.AssertAllStagesStopped(() =>
            {
                WithSubstreamsSupport(2, run: (masterSubscriber, masterSubscription, getSubFlow) =>
                {
                    var s1 = new StreamPuppet(getSubFlow(1).RunWith(Sink.AsPublisher<int>(false), Materializer), this);
                    masterSubscriber.ExpectNoMsg(TimeSpan.FromMilliseconds(100));

                    s1.ExpectNoMsg(TimeSpan.FromMilliseconds(100));
                    s1.Request(1);
                    s1.ExpectNext(1);
                    s1.ExpectNoMsg(TimeSpan.FromMilliseconds(100));

                    var s2 = new StreamPuppet(getSubFlow(0).RunWith(Sink.AsPublisher<int>(false), Materializer), this);
                    s2.ExpectNoMsg(TimeSpan.FromMilliseconds(100));
                    s2.Request(2);
                    s2.ExpectNext(2);
                    // Important to request here on the OTHER stream because the buffer space is exactly one without the fanout box
                    s1.Request(1);
                    s2.ExpectNext(4);

                    s2.ExpectNoMsg(TimeSpan.FromMilliseconds(100));

                    s1.ExpectNext(3);

                    s2.Request(1);
                    // Important to request here on the OTHER stream because the buffer space is exactly one without the fanout box
                    s1.Request(1);
                    s2.ExpectNext(6);
                    s2.ExpectComplete();

                    s1.ExpectNext(5);
                    s1.ExpectComplete();
                    masterSubscription.Request(1);
                    masterSubscriber.ExpectComplete();
                });
            }, Materializer);
        }