- Depending on the exact execution order of timers with same
  expiration time, the exact results would depend on whether the
  "close" timer was the first or second of those two.
- Do a two phase close; first time around just go to a draining
  mode. Then after all activity has been drained, delete the
  object properly.
- Also gives us a more diverse event mix, since it currently
  might not have quite enough medium length timers that actually
  get executed.