Akka.Streams.Tests.Dsl.SourceSpec.Maybe_Source_must_allow_external_triggering_of_OnError C# (CSharp) Метод

        public void Maybe_Source_must_allow_external_triggering_of_OnError()
        {
            this.AssertAllStagesStopped(() =>
            {
                var neverSource = Source.Maybe<int>();
                var counterSink = Sink.First<int>();

                var t = neverSource.ToMaterialized(counterSink, Keep.Both).Run(Materializer);
                var neverPromise = t.Item1;
                var counterFuture = t.Item2;

                //external cancellation
                neverPromise.SetException(new Exception("Boom"));

                counterFuture.Invoking(f => f.Wait(500)).ShouldThrow<Exception>()
                    .WithMessage("Boom");
            }, Materializer);
        }