Summary:
This PR has two commits:
1. Modify the code to allow different Lock Managers (of any kind) to be used. It is implied that a LockManager uses its own custom LockTracker.
2. Add definitions for Range Locking (class Endpoint and GetRangeLock() function.
cheng-chang, is this what you've had in mind (should the PR have both item 1 and item 2?)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7443
Reviewed By: zhichao-cao
Differential Revision: D24123172
Pulled By: cheng-chang
fbshipit-source-id: c6548ad6d4cc3c25f68d13b29147bc6fdf357185
Sergei Petrunia