AsyncDolls.AsyncDollsRecurseFree.PushMessages.StartAsync C# (CSharp) Method

        public Task StartAsync(Func<TransportMessage, Task> onMessage)
        {
            onMessageAsync = onMessage;

            runningTasks = new ConcurrentDictionary<Task, Task>();
            semaphore = new SemaphoreSlim(maxConcurrency);
            tokenSource = new CancellationTokenSource();
            var token = tokenSource.Token;

            pumpTask = Task.Run(async () =>
            {
                while (!token.IsCancellationRequested)
                {
                    await semaphore.WaitAsync(token).ConfigureAwait(false);

                    TransportMessage message;
                    if (messages.TryDequeue(out message))
                    {
                        var task = onMessageAsync(message);

                        runningTasks.TryAdd(task, task);

                        task.ContinueWith(t =>
                        {
                            semaphore.Release();
                            Task taskToBeRemoved;
                            runningTasks.TryRemove(t, out taskToBeRemoved);
                        }, TaskContinuationOptions.ExecuteSynchronously)
                            .Ignore();
                    }
                    else
                    {
                        await Task.Delay(TimeSpan.FromMilliseconds(20), token).ConfigureAwait(false);
                    }

                }
            }, token);

            return Task.CompletedTask;
        }

        public async Task Do()
        {
            var messages = new ConcurrentQueue <TransportMessage>();

            messages.Enqueue(new TransportMessage());
            messages.Enqueue(new TransportMessage());
            messages.Enqueue(new TransportMessage());

            var countdown = new AsyncCountdownEvent(3);

            var chainFactory = new ChainFactory();

            chainFactory.Register(() => new LogElement(countdown));
            chainFactory.Register(() => new DelayBefore());
            chainFactory.Register(() => new DelayBefore());
            chainFactory.Register(() => new DelayBefore());
            chainFactory.Register(() => new DelayBefore());
            chainFactory.Register(() => new DelayBefore());
            chainFactory.Register(() => new DelayBefore());
            chainFactory.Register(() => new DelayAfter());
            chainFactory.Register(() => new DelayAfter());
            chainFactory.Register(() => new DelayAfter());
            chainFactory.Register(() => new DelayAfter());
            chainFactory.Register(() => new DelayAfter());
            chainFactory.Register(() => new DelayInUsing());
            chainFactory.Register(() => new DelayBefore());
            chainFactory.Register(() => new DelayAfter());
            chainFactory.Register(() => new DelayBefore());
            chainFactory.Register(() => new DelayAfter());
            chainFactory.Register(() => new PassThrough());
            chainFactory.Register(() => new PassThrough());
            chainFactory.Register(() => new PassThrough());
            chainFactory.Register(() => new DelayInUsing());
            chainFactory.Register(() => new DelayBefore());
            chainFactory.Register(() => new DelayAfter());
            chainFactory.Register(() => new PassThrough());
            chainFactory.Register(() => new PassThrough());
            chainFactory.Register(() => new PassThrough());
            chainFactory.Register(() => new ThrowException());

            var pushMessages = new PushMessages(messages, maxConcurrency: 1);

            await pushMessages.StartAsync(tm => Connector(chainFactory, tm));

            await Task.Delay(2000);

            await pushMessages.StopAsync();
        }