How to pass LongRunning flag specifically to Task.Run()?

Question

I need a way to set an async task as long running without using Task.Factory.StartNew(...) and instead using Task.Run(...) or something similar.

Context:

I h

Answer 1

The real issue you have here is that your operation is not in fact long running. The actual work you're doing is an asynchronous operation, meaning it will return to the caller basically immediately. So not only do you not need to use the long running hint when having the task scheduler schedule it, there's no need to even use a thread pool thread to do this work, because it'll be basically instantaneous. You shouldn't be using StartNew or Run at all, let alone with the long running flag.

So rather than taking your asynchronous method and starting it in another thread, you can just start it right on the current thread by calling the asynchronous method. Offloading the starting of an already asynchronous operation is just creating more work that'll make things slower.

So your code simplifies all the way down to:

var cts = new CancellationTokenSource();
Task t = DoWork();
async Task DoWork()
{
    while (true)
    {
        cts.Token.ThrowIfCancellationRequested();
        try
        {
            "Running...".Dump();
            await Task.Delay(500, cts.Token);
        }
        catch (TaskCanceledException) { }
    }
}