code: func milliTime() (r []byte) {
  	buf := new(bytes.Buffer)
  	t := time.Now().UnixNano()
  	m := t / 1e6
  	binary.Write(buf, binary.BigEndian, m)
  	return buf.Bytes()[2:]
  }
docs: // milliTime returns a 6 byte slice representing the unix time in milliseconds