private GifBitmapWrapper decodeStream(ImageVideoWrapper source, int width, int height, byte[] bytes)
            throws IOException {
        InputStream bis = streamFactory.build(source.getStream(), bytes);
        bis.mark(MARK_LIMIT_BYTES);
        ImageHeaderParser.ImageType type = parser.parse(bis);
        bis.reset();

        GifBitmapWrapper result = null;
        if (type == ImageHeaderParser.ImageType.GIF) {
            result = decodeGifWrapper(bis, width, height);
        }
        // Decoding the gif may fail even if the type matches.
        if (result == null) {
            // We can only reset the buffered InputStream, so to start from the beginning of the stream, we need to
            // pass in a new source containing the buffered stream rather than the original stream.
            ImageVideoWrapper forBitmapDecoder = new ImageVideoWrapper(bis, source.getFileDescriptor());
            result = decodeBitmapWrapper(forBitmapDecoder, width, height);
        }
        return result;
    }
An {@link ResourceDecoder} that can decode either an {@link Bitmap} or an {@link GifDrawable}
from an {@link InputStream} or a {@link android.os.ParcelFileDescriptor ParcelFileDescriptor}.
core/src/main/java/com/bumptech/glide/load/resource/gifbitmap/GifBitmapWrapperResourceDecoder.java