docs: private static boolean isGifHeader(final byte[] imageHeaderBytes, final int headerSize) {
      if (headerSize < GIF_HEADER_LENGTH) {
        return false;
      }
      return ImageFormatCheckerUtils.startsWithPattern(imageHeaderBytes, GIF_HEADER_87A) ||
          ImageFormatCheckerUtils.startsWithPattern(imageHeaderBytes, GIF_HEADER_89A);
    }