LibUsbDotNet | My updates to LibUsbDotNet, an excellent library for cross-platform USB device control using Mono/.N | Change Data Capture library

First of all, you are using DispatchTimer, this will raise ticks on the UI thread. So as far as I can see there is no multi threading going on in the example. There are other timers, like System.Timers.Timer that raises events on a background thread if that is the intent. But if you just want to check and update status every so often, and are not running any code that blocks, just using the UI thread is fine and will simplify things a lot.

Even if we assume ProductOrganizationHandler did run on a worker thread, it would still be generally safe to remove items from one concurrent collection and putting them in another. But it would not guarantee that items are processed in any particular order, nor that any specific item is processed by a given tick of the timer. But since the timer will tick periodically all the items should eventually be processed. Keep in mind that most timers need to be disposed, so you need to handle that somehow, including if the processing is stopped prematurely.

Keep in mind that async does not mean concurrent, so I would not use it unless your USB library provides async methods. Even then I would avoid async void since this promotes exceptions to the captured synchronization context, potentially crashing the application, so it should mostly be used in the outermost layer, like button event handlers, or timers, and then you should probably handle exceptions somehow.

As for the best way to do it, I would take a look at DataFlow library.