Support for draft-bellis-dnsop-xpf or PROXYv2

I would be interested in seeing draft-bellis-dnsop-xpf revived and implemented in Knot DNS. It looks like there is some support for XPF in other DNS servers (dnsdist, PowerDNS Recursor).

My use case is developing a dnstap-based utility that can re-send queries to a nameserver and convert the dnstap query_address field to an XPF record appended to the query and being able to validate that the same RRsets were returned. If there's any behavior that varies based on the remote IP that sent the query this wouldn't be reflected if the utility is just re-sending the query.

Thanks for considering!