Summary:
One design goal of sonar is to never cause the host app to crash or hang.
For this reason, we do all heavy work in a background thread.
If we detect that it's not running in it's own thread, just return so we don't hold up the caller.
Reviewed By: danielbuechele
Differential Revision: D8767288
fbshipit-source-id: e146cc2cfe5c3e62d12f527ff79f24c74873d4ff
d0ecb46d64