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    <p>If performance is what you're after, and async at its finest level, I suggest looking into Completion Ports. This is what is ultimately underneath, hidden in the Windows Kernel, and it's awesome. When I used them, I used C++, even found a Kernel bug because of it, <strong>but</strong> I was limited to the language. </p> <p>I've seen <a href="http://www.codeproject.com/KB/cs/managediocp.aspx" rel="nofollow">this article</a> on CodeProject which might be worth exploring to see where you can take your idea further and/or use the code that's there.</p> <p>The nature of Completion ports is to work on callbacks. That is, in general, you "put" a request in the queue, and when something lands there, the request is read and the callback specified is read. It is in fact, a queue, but like I said, at the lowest (manageable) level (before getting almost on metal).</p> <p><strong>EDIT:</strong> I've written a sort of a FTP server/client testing utility with Completion ports, so the base process is the same - reading and writing of commands in a <em>queuable</em> fashion. Hope it helps.</p> <p><strong>EDIT #2:</strong> Ok, here's what I would do, based on your feedback and comments. I would have an "outgoing queue", <code>ConcurrentQueue&lt;Message&gt;</code>. You can have a separate thread for sending messages by dequeueing each message. <em>Note, if you want it a bit more "safe", I suggest peeking at the message, sending it, then dequeuing it.</em> Anyway, the Message class can be internal, and look something like this:</p> <pre><code>private class Message { public string Command { get; set; } ... additonal properties, like timeouts, etc. ... } </code></pre> <p>In the singleton class (I'll call it <code>CommunicationService</code>), I'd also have a <code>ConcurrentBag&lt;Action&lt;Response&gt;&gt;</code>. This is now where the fun starts :o). When a separate concern wants to do something, it registeres itself, for example, if you have a <code>TemepratureMeter</code> I would have it do something like this:</p> <pre><code>public class TemperatureMeter { private AutoResetEvent _signal = new AutoResetEvent(false); public TemperatureMeter { CommunicationService.AddHandler(HandlePotentialTemperatureResponse); } public bool HandlePotentialTemperatureResponse(Response response) { // if response is what I'm looking for _signal.Set(); // store the result in a queue or something =) } public decimal ReadTemperature() { CommunicationService.SendCommand(Commands.ReadTemperature); _signal.WaitOne(Commands.ReadTemperature.TimeOut); // or smth like this return /* dequeued value from the handle potential temperature response */; } } </code></pre> <p>And now, in your CommunicationService, when you receive a response, you simply to a</p> <pre><code>foreach(var action in this._callbacks) { action(rcvResponse); } </code></pre> <p>Voila, separation of concerns. Does it answer your question any better?</p> <p>Another possible tactic would be, to couple message and callback, but having the Callback be a <code>Func&lt;Response, bool&gt;</code> and the dispatcher thread checks if the result returned from the Func is true, then this callback is <em>disposed</em>.</p>
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    1. POProviding Asynchronous Serial Port Communication
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    1. USAnže Vodovnik
    1. USAnže Vodovnik
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    1. POProviding Asynchronous Serial Port Communication
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    1. COThis is quite interesting, and I'll give it a look. In this particular scenario, we're less concerned with performance and more about management of concerns. The `Arduino` class should not care what is done with the data (as it does now), it should leave that responsibility with whichever classes were responsible for sending the originating commands. Considering only <100 of these commands are sent per minute, performance is not critical, but this will be interesting reading for sure.
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    2. COCan your responses be sent out of order? Or is it always so that your underlying system will process them in a queued fashion?
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    3. COThey can be sent at any time, in any order. Various components in the system will make requests at near-random times, and the microcontroller will process them somewhat asynchronously. For example, one component may request the temperature, which is a fast operation, while another component is moving a stepper motor, which takes longer. The sensor request and reply may happen all during the motor operation. The requests are processed linearly, but the replies I get come in no particular order.
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