code: public boolean isInDiskCacheSync(final ImageRequest imageRequest) {
      final CacheKey cacheKey = mCacheKeyFactory.getEncodedCacheKey(imageRequest, null);
      final ImageRequest.CacheChoice cacheChoice = imageRequest.getCacheChoice();
  
      switch (cacheChoice) {
        case DEFAULT:
          return mMainBufferedDiskCache.diskCheckSync(cacheKey);
        case SMALL:
          return mSmallImageBufferedDiskCache.diskCheckSync(cacheKey);
        default:
          return false;
      }
    }
docs: Performs disk cache check synchronously. It is not recommended to use this
  unless you know what exactly you are doing. Disk cache check is a costly operation,
  the call will block the caller thread until the cache check is completed.
  
  @param imageRequest the imageRequest for the image to be looked up.
  @return true if the image was found in the disk cache, false otherwise.