Summary:
When using lock-holder objects, it is typically required to conduct all unlocking and relocking through them. That way, the RAII lock-holder does not attempt to unlock an unlocked mutex should the code throw after unlocking but before relocking.
Changelog: [internal]
Reviewed By: sammy-SC
Differential Revision: D29238721
fbshipit-source-id: 2403ce8c9e86f96b56a35a456e017486a2854c74