Registry.Get used a full sort to get the minimum of a list, and the sort
was broken because util.AddressUnspecifiedLess assumed it could find out
whether an address is IPv4 or IPv6 from its Network method. However,
net.(TCP|UDP)Addr.Network always returns "tcp"/"udp".
This does two things:
- Exclude QUIC from go1.16 builds, automatically, for now, since it
doesn't work and just panics.
- Provide some fake listeners and dialers when QUIC is disabled.
These fake listeners and dialers indicate that they are disabled and
unsupported, which silences "Dialing $address: unknown address scheme:
quic" type of stuff which is not super helpful to the user.
The QUIC package is notorious for being incompatible with either too
old or too new Go releases. Currently it doesn't build with Go 1.15 RC
and I want to test the rest with Go 1.15. With this I can do `go run
build.go --tags noquic` to do that.
