No more dll, so switch the text to call out the profiling of the worker thread instead. Even though all the logic has been moved into Unity, we can't easily simplify the worker thread profiling logic because of the simple fact that we need to construct CustomSampler objects on the main thread, so all the existing back and forth still needs to be performed.

To test:

• Make sure ServiceProvider and XRServiceProvider both look correct in the inspector and have good tooltips.