docs: private BinaryResource endInsert(
        final DiskStorage.Inserter inserter,
        final CacheKey key,
        String resourceId) throws IOException {
      synchronized (mLock) {
        BinaryResource resource = inserter.commit(key);
        mResourceIndex.add(resourceId);
        mCacheStats.increment(resource.size(), 1);
        return resource;
      }
    }