Most of the developers emailing their users in panic are not in this situation though. They're writing audio plugins using the AU or VST APIs. They don't ever

Most of the developers emailing their users in panic are not in this situation though. They're writing audio plugins using the AU or VST APIs. They don't ever touch hardware or even deal with realtime constraints directly : they just fill buffers as far as they can and pass them on to the host DAW application, which together with audio interface drivers + the OS deal with the hard stuff.