@Override
  public String toString() {
    return Objects.toStringHelper(this)
        .add("uri", mSourceUri)
        .add("cacheChoice", mCacheChoice)
        .add("decodeOptions", mImageDecodeOptions)
        .add("postprocessor", mPostprocessor)
        .add("priority", mRequestPriority)
        .add("resizeOptions", mResizeOptions)
        .add("rotationOptions", mRotationOptions)
        .add("bytesRange", mBytesRange)
        .add("resizingAllowedOverride", mResizingAllowedOverride)
        .add("downsampleOverride", mDownsampleOverride)
        .add("progressiveRenderingEnabled", mProgressiveRenderingEnabled)
        .add("localThumbnailPreviewsEnabled", mLocalThumbnailPreviewsEnabled)
        .add("loadThumbnailOnly", mLoadThumbnailOnly)
        .add("lowestPermittedRequestLevel", mLowestPermittedRequestLevel)
        .add("cachesDisabled", mCachesDisabled)
        .add("isDiskCacheEnabled", mIsDiskCacheEnabled)
        .add("isMemoryCacheEnabled", mIsMemoryCacheEnabled)
        .add("decodePrefetches", mDecodePrefetches)
        .add("delayMs", mDelayMs)
        .toString();
  }
Returns whether the use of the cache is enabled for read or write according to given mask.
imagepipeline/src/main/java/com/facebook/imagepipeline/request/ImageRequest.java