Code review comment for lp:~vanvugt/mir/ddouble

set_scaling_delay was only just added to satisfy Alberto. I preferred not having that at all because in the absence of bugs (and none are known) it makes no sense to ever turn it off. That just allows people to shoot themselves in the proverbial foot, performance wise. Throughput is never compromised so it should always be turned on. Although it does help with a couple of tests that are invalid with queue scaling so would need to be deleted/disabled in the absence of set_scaling_delay.

The sleep_for was not my first preference. I toyed a lot with timerless tests but what I found was that they were nowhere near as effective at finding subtle bugs (when I intentionally introduced them) as the tests using real time. So I switched back to using real time because they're stronger tests more sensitive to subtle mistakes. Just as the existing `slow_client_framerate_matches_compositor' is so effective it continues to surprise me.

Yeah that cast is there for readability. If I said:
  int x = buffers.size();
  if (x < nbuffers)
then no one would complain. It's all the same and not something we should bother blocking on. The current form is more readable.