I think you mean pre-emptively scheduled, otherwise blocking would be very bad indeed. 
I have one API route that takes the user’s data and generates a big CSV file out of it. It can take a long time and be CPU intensive. I like that I don’t have to fork it out to a background task, but instead I can just handle it in the request directly. The client sets a longer timeout and shows a progress indicator for that route to take care of the user experience.
