public @Nullable CloseableReference<Bitmap> getPreviewBitmap() {
    return CloseableReference.cloneOrNull(mPreviewBitmap);
  }
Gets the preview bitmap. This method returns a new reference. The caller must close it.

@return the reference to the preview bitmap or null if none was set. This returns a reference
    that must be released by the caller
animated-base/src/main/java/com/facebook/imagepipeline/animated/base/AnimatedImageResultBuilder.java