Akka.Streams.Tests.Dsl.FlowIdleInjectSpec.KeepAlive_must_work_if_timer_fires_before_initial_request C# (CSharp) Method

        public void KeepAlive_must_work_if_timer_fires_before_initial_request()
        {
            var upstream = TestPublisher.CreateProbe<int>(this);
            var downstream = TestSubscriber.CreateProbe<int>(this);

            Source.FromPublisher(upstream)
                .KeepAlive(TimeSpan.FromSeconds(1), () => 0)
                .RunWith(Sink.FromSubscriber(downstream), Materializer);

            downstream.EnsureSubscription();
            downstream.ExpectNoMsg(TimeSpan.FromSeconds(1.5));
            downstream.Request(1);
            downstream.ExpectNext(0);

            upstream.SendComplete();
            downstream.ExpectComplete();
        }