TPL DataFlow sample.cs

private static readonly BufferBlock<string> Buffer = new BufferBlock<string>();

static void Main(string[] args)
{
    Enumerable.Range(0, 100).ToList().ForEach(i => Buffer.SendAsync("Mesage #" + i));

    var consumer = new ActionBlock<string>(s => Process(s), new ExecutionDataflowBlockOptions { MaxDegreeOfParallelism = 5 });
    Buffer.LinkTo(consumer);
    Buffer.Completion.ContinueWith(t => consumer.Complete());

    Console.WriteLine("Running");
    Console.ReadLine();

    Buffer.Complete();

    consumer.Completion.Wait();

    Console.WriteLine("Completed");
    Console.ReadLine();
}


private static void Process(string message)
{
    Thread.Sleep(250);
    string msg = Thread.CurrentThread.ManagedThreadId + " : " + message;
    Console.WriteLine(msg);
    //messages.Add(msg);
}