private static MessageDigest digest(MessageDigest md, UUID uid) {
        if (uid != null) {
            long msb = uid.getMostSignificantBits();
            digest(md, msb);
            long lsb = uid.getLeastSignificantBits();
            digest(md, lsb);
        }
        return md;
    }
Updates a digest with a uuid.
@param md the digest to update
@param uid the uuid
standalone-metastore/metastore-common/src/main/java/org/apache/hadoop/hive/metastore/properties/Digester.java