The alphabetical order of HostAndPort entries is significant in targeting hedged reads.
But the order we use doesn't seem proper, as it's relying on the HostAndPort::toString.

https://github.com/mongodb/mongo/blob/2c77d92ddcd9b1157cd13fb97dd3580b67e205a1/src/mongo/executor/network_interface_tl.cpp#L534-L541

 if (targetHostsInAlphabeticalOrder) {
        // Sort the target hosts by host names.
        std::sort(request.target.begin(),
                  request.target.end(),
                  [](const HostAndPort& target1, const HostAndPort& target2) {
                      return target1.toString() < target2.toString();
                  });
    }

I can see a few problems with this.

• DNS is case-insensitive, but this sort is not.

• IPv6 addresses start with a "[", an ASCII character that falls between the A-Z and a-Z character ranges, so a hybrid IPv6/IPv4 set will I suppose end up with a the IPv4 addrs ordered with the uppercase hosts, then ALL the IPv6 hosts, and then the lowercase hosts. This is definitely not the intent of the sort.

• It's expensive to compute toString on each of the NlogN comparisons of a sort.