Summary:
The stall watchdog is handy to detect stalls, but it doesn't really tell us what was
happening. This diff makes it easy to track React perf and bridge traffic during any stall, and
prints it out if the stall exceeds the threshold.
Reviewed By: yungsters
Differential Revision: D4479439
fbshipit-source-id: 87f94913ec341a648d7744249597dc30b29759ab
Spencer Ahrens