public static String makeAPP1_EXIF(String tiff) {
    String app1Length = encodeInt2HexString(numBytes(tiff) + 8, 2, false);
    return APP1_MARKER + app1Length + APP1_EXIF_MAGIC + tiff;
  }
Provide test use functions for JfifUtilTest.
imagepipeline-base/src/test/java/com/facebook/imageutils/JfifTestUtils.java