Summary:
Range Locking - an implementation based on the locktree library
- Add a RangeTreeLockManager and RangeTreeLockTracker which implement
range locking using the locktree library.
- Point locks are handled as locks on single-point ranges.
- Add a unit test: range_locking_test
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7506
Reviewed By: akankshamahajan15
Differential Revision: D25320703
Pulled By: cheng-chang
fbshipit-source-id: f86347384b42ba2b0257d67eca0f45f806b69da7