Rewritten in significant part by tabbott to actually be correct.
One particularly nasty thing the original webhook integration did is
do `current_time = time.time()` at the top of the `view.py` function
-- that means that code ran at import time, not runtime.
There's probably follow-up work to do here to eliminate these
completely, but this dramatically shrinks the ~1 minute race window
that was previously present between import and test function being
called.
