Adding a flag for RDNS domain

I want to create whitelisting in our firewall for specific RDNS entries because I don't know the PrimaryIPv4 address of the machine that will be created.

Is it possible to add a flag for providing a domain that is used for the RDNS pointer?

I am a go newbie. Would something like this work?

func (d *Driver) setupRDNS() error {
	if d.RDNSDomain == "" {
		return nil
	}
	log.Infof("configuring RDNS ...")
	opts := hcloud.PrimaryIPChangeDNSPtrOpts{
		DNSPtr: d.MachineName + "." + d.RDNSDomain,
	}
	act, _, err := d.getClient().PrimaryIP.ChangeDNSPtr(context.Background(), opts)

	if err != nil {
		return fmt.Errorf("could not change DNS pointer: %w", err)
	}

	return d.waitForAction(act)
}

The issue names Driver.setupRDNS and hcloud.PrimaryIP.ChangeDNSPtr, but no repository file or test. Start by locating the driver setup and flag definitions, then verify the flag reaches RDNS configuration and the relevant driver tests cover the requested behavior.