code: func generateMacAddress() (net.HardwareAddr, error) {
  	mac := []byte{
  		2,          // locally administered unicast
  		0x65, 0x02, // OUI (randomly chosen by jell)
  		0, 0, 0, // bytes to randomly overwrite
  	}
  
  	_, err := rand.Read(mac[3:6])
  	if err != nil {
  		return nil, errwrap.Wrap(errors.New("cannot generate random mac address"), err)
  	}
  
  	return mac, nil
  }
docs: // generateMacAddress returns net.HardwareAddr filled with fixed 3 byte prefix
  // complemented by 3 random bytes.