docs: public synchronized void release(int key, T value) {
      LinkedEntry<T> bucket = mMap.get(key);
      if (bucket == null) {
        bucket = new LinkedEntry<T>(null, key, new LinkedList<T>(), null);
        mMap.put(key, bucket);
      }
  
      bucket.value.addLast(value);
  
      moveToFront(bucket);
    }