@Override
  public <T> T getExtra(String key, @Nullable T valueIfNotFound) {
    Object value = mExtras.get(key);
    if (value == null) {
      return valueIfNotFound;
    }
    //noinspection unchecked
    return (T) value;
  }
Sets extras that match mImageExtrasList to this image from supplied extras
imagepipeline-base/src/main/java/com/facebook/imagepipeline/image/BaseCloseableImage.java