code: public static byte[] asByteArray(UUID uuid) {
          long msb = uuid.getMostSignificantBits();
          long lsb = uuid.getLeastSignificantBits();
          byte[] buf = new byte[16];
          for (int i = 0; i < 8; i++) {
              buf[i]     = (byte) (msb >>> 8 * (7 - i));
              buf[i + 8] = (byte) (lsb >>> 8 * (7 - i));
          }
          return buf;
      }
docs: Returns the byte-array equivalent of the specified UUID in big-endian order.