lacp_format_partner
lacp_format_partner(a, astr, sizeof(astr)),
lacp_format_partner(b, bstr, sizeof(bstr)));
lacp_format_partner(&du->ldu_actor, buf, sizeof(buf)));
lacp_format_partner(&du->ldu_partner, buf, sizeof(buf)));
const char *lacp_format_partner(const struct lacp_peerinfo *, char *, size_t);