code: func (retriever *macAddressRetriever) retrieveOnce() error {
  	dev := filepath.Base(retriever.dev)
  	link, err := retriever.netlinkClient.LinkByName(dev)
  	if err != nil {
  		return apierrors.NewRetriableError(apierrors.NewRetriable(false), err)
  	}
  	retriever.macAddress = link.Attrs().HardwareAddr.String()
  	return nil
  }
docs: // retrieveOnce retrieves the MAC address of a device using netlink.LinkByName