Type Definition parking_lot::MappedRwLockReadGuard

type MappedRwLockReadGuard<'a, T> = MappedRwLockReadGuard<'a, ParkingLotRwLock, T>;

An RAII read lock guard returned by RwLockReadGuard::map, which can point to a subfield of the protected data.

The main difference between MappedRwLockReadGuard and RwLockReadGuard is that the former doesn't support temporarily unlocking and re-locking, since that could introduce soundness issues if the locked object is modified by another thread.