akkadotnet/akka.net

I have a question about running Akka streams in transactional manner, when success or failure can trigger some acknowedgement process. Let's say I have a simple stream:

        var source = Source.From(Enumerable.Range(1, 10));
        var flow = Flow.FromFunction(new Func<int, int>(x =>
        {
            if (x == 5)
                throw new ArgumentException();
            return x*2;
        })).WithAttributes(ActorAttributes.CreateSupervisionStrategy(Deciders.ResumingDecider));
        var writeSink = Sink.ForEach<int>(Console.WriteLine);
        var runnable = source.Via(flow).To(writeSink);
        runnable.Run(materializer);

As you can see, when the flow encounters an element 5, it will raise an exception. How can this exception trigger some negative acknowledgemen (i.e. nack a queue message with certain tag)? And if the message flow through the whole stream, how can messaging processing completing trigger a positive acknowledgement? Of course I would like to run such acknowledgement outside individual stream elements.