+6249. [cleanup] Reduce the number of reserved UDP dispatches
+ to the number of loops, replace the round-robin
+ mechanism in dns_dispatchset_t with dispatches
+ pinned to loops, and use lock-free hash tables
+ for looking up query IDs and active TCP
+ connections. [GL !8304]
+
6248. [func] Add an option "resolver-use-dns64", which enables
application of DNS64 rules to server addresses
when sending recursive queries. This allows