Rather than having an expensive 'expired' (fka 'stale_ttl') in the rdataset structure, that is only used to be printed in a comment on ancient RRsets, reuse the TTL field of the RRset.
Rather than having an expensive 'expired' (fka 'stale_ttl') in the rdataset structure, that is only used to be printed in a comment on ancient RRsets, reuse the TTL field of the RRset.