void offer(WriteLock writeLock) {
            synchronized (pool) {
                if (pool.size() < MAX_POOL_SIZE) {
                    pool.offer(writeLock);
                }
            }
        }
Keeps a map of keys to locks that allows locks to be removed from the map when no longer in use
so the size of the collection is bounded.

<p> This class will be accessed by multiple threads in a thread pool and ensures that the
 number of threads interested in each lock is updated atomically so that when the count reaches
 0, the lock can safely be removed from the map. </p>
core/src/main/java/com/bumptech/glide/load/engine/cache/DiskCacheWriteLocker.java