Fix all but one workers disappearing.
Fix all but one workers disappearing.

- python3.8 had a backwards incompatability that broke some
  uses of async generators. Fixed by making the sweep generator
  synchronous. Hopefully the interface isn't stalled when looking
  for a pending status that is far away.

ahamilton/vigil,ahamilton/vigil,ahamilton/vigil,ahamilton/vigil,ahamilton/vigil,ahamilton/vigil,ahamilton/vigil,ahamilton/vigil,ahamilton/vigil