code: func uuidToUint64(uuid string) uint64 {
  	lower := uuid[0:8] + uuid[9:13] + uuid[14:18]
  	upper := uuid[19:23] + uuid[24:36]
  	lowVal, err := strconv.ParseUint(lower, 16, 64)
  	if err != nil {
  		panic("Failed to convert " + lower)
  	}
  	highVal, err := strconv.ParseUint(upper, 16, 64)
  	if err != nil {
  		panic("Failed to convert " + upper)
  	}
  	return lowVal ^ highVal
  }
docs: // uuidToUint64 is a bit of a hack to generate a 64bit Consul index.
  // In effect, we take our random UUID, convert it to a 128 bit number,
  // then XOR the high-order and low-order 64bit's together to get the
  // output. This lets us generate an index which can be used to simulate
  // the blocking behavior of other catalog endpoints.