code: public Task<EncodedImage> get(CacheKey key, AtomicBoolean isCancelled) {
      try {
        if (FrescoSystrace.isTracing()) {
          FrescoSystrace.beginSection("BufferedDiskCache#get");
        }
        final EncodedImage pinnedImage = mStagingArea.get(key);
        if (pinnedImage != null) {
          return foundPinnedImage(key, pinnedImage);
        }
        return getAsync(key, isCancelled);
      } finally {
        if (FrescoSystrace.isTracing()) {
          FrescoSystrace.endSection();
        }
      }
    }
docs: Performs key-value look up in disk cache. If value is not found in disk cache staging area
  then disk cache read is scheduled on background thread. Any error manifests itself as
  cache miss, i.e. the returned task resolves to null.
  @param key
  @return Task that resolves to cached element or null if one cannot be retrieved;
  returned task never rethrows any exception