core.fsmonitor always perform rescans

Hello,

I'm facing issue with core.fsmonitor.

I'm currently using the provided watchman hook, but it doesn't seem to
record the fact that it has queried the fsmonitor backend, and as a
result the timestamp passed to the hook doesn't seem to change.

As it always pass a timestamp before watchman has crawled the
directories, watchman will always return all files inside the
directory. This happens everytime I run a git command, resulting in
slowness.

Is the timestamp not being updated an intended behavior, or is this a bug?

Tatsuyuki Ishi