320 struct LocalLockHolder {  struct
321     using WeakPointer = std::weak_ptr<Mutex>;
322     using StrongPointer = std::shared_ptr<Mutex>;
323     using Map = std::unordered_map<Key, WeakPointer>;
324     using MapLock = std::recursive_mutex;
326     LocalLockHolder(Key key, Map& map, MapLock& mapLock)  in LocalLockHolder()  argument
339     LocalLockHolder(LocalLockHolder&& other) noexcept  in LocalLockHolder()  argument
346     ~LocalLockHolder() {  in ~LocalLockHolder()
365     void lock() { mRefLock->lock(); }  in lock()
366     void unlock() { mRefLock->unlock(); }  in unlock()
367     void lock_shared() { mRefLock->lock_shared(); }  in lock_shared()
368     void unlock_shared() { mRefLock->unlock_shared(); }  in unlock_shared()
371     Key mKey;
372     Map& mMap;
373     MapLock& mMapLock;
374     StrongPointer mRefLock;