This gives the integration-style CLI-based tests a chance
to set the delay to 0 before the first 3-second delayed
call is queued to _lazy_tail in the Downloader
1. Split alice/bob clocks to avoid races conditions
in the tests
2. Wrap ._notify so we can advance the clock after inotify
calls in the RealTest (since it takes >0ms to do the "real" notifies)
