@Override
    public InputStream loadData(Priority priority) throws Exception {
        ThumbnailStreamOpener fetcher = factory.build(mediaStoreUri, width, height);

        if (fetcher != null) {
            inputStream = openThumbInputStream(fetcher);
        }

        if (inputStream == null) {
            inputStream = defaultFetcher.loadData(priority);
        }

        return inputStream;
    }
A DataFetcher that retrieves an {@link InputStream} for a local Uri that may or may not be for a resource
in the media store. If the local Uri is for a resource in the media store and the size requested is less than or
equal to the media store thumbnail size, preferentially attempts to fetch data for the pre-generated media store
thumbs using {@link MediaStore.Images.Thumbnails} and
{@link MediaStore.Video.Thumbnails}.
core/src/main/java/com/bumptech/glide/load/data/MediaStoreThumbFetcher.java