Pkdns: DNS server resolving via mainline DHT

Creator here. It takes around 30ms to resolve a public key DNS entry on the DHT. After the first resolution, the entry is obviously cached according to the configured time-to-live (ttl).

It's not as fast as regular DNS, 30ms is still very quick.

We use pkarr at iroh.computer for node discovery. It is anything but slow. It is very rare for a lookup to take more than a few milliseconds. It is sometimes faster than our non-p2p node discovery option which is using DNS.

DHTs get a bad rap because of many recent DHTs that were horribly inefficient. But mainline is different. Many of the design decisions of mainline seem very limiting at first, but make a lot of sense for perf.

E.g. a pkarr record can only be 1000 bytes, so the entire message fits into a single non-fragmented UDP packet.