LOC records have a version field. So far only version 0 has been
published, but if a record with a different version was encountered,
our only recourse is to treat it as an unknown type. This is
implemented with the 'unparseable' flag, which causes the
serialization/deserialization and printing function to cause the
record as a blob. The flag can be used if other packet types cannot be
parsed for whatever reason.
Let's turn resolved into a something truly useful: a fully asynchronous
DNS stub resolver that subscribes to network changes.
(More to come: caching, LLMNR, mDNS/DNS-SD, DNSSEC, IDN, NSS module)