consider issuing NEW_TOKEN frames that validate more than one address

[divagant-martian]

The contents of NEW_TOKEN frames is interely implementation specific.
Currently, these frames are issued with a single IP address, but with multipath
several address can be validated. This is possible with non multipath as well,
but multipath puts this case on the front. noq should either issue tokens for
multiple addresses or address-independent tokens (AFAIU this is allowed).

[flub]

https://www.rfc-editor.org/rfc/rfc9000.html#section-8.1.4-4

Servers can use tokens from NEW_TOKEN frames in deciding not to send a Retry packet, even if the client address has changed. If the client IP address has changed, the server MUST adhere to the anti-amplification limit; see Section 8.

But at the same time, from the same paragraph:

Tokens sent in NEW_TOKEN frames MUST include information that allows the server to verify that the client IP address has not changed from when the token was issued.

And of course multipath itself says, https://www.ietf.org/archive/id/draft-ietf-quic-multipath-21.html#section-3.1.3

[...] a server SHOULD issue tokens that are capable of validating any of the previously validated addresses.