The server address the client was asked to connect to. Carries the full
list of addresses the host resolved to (used for Happy Eyeballs racing
during connect — see client::happy_eyeballs_connect) and the original
host string from the CLI (used as the default SNI value during the TLS
handshake — see client_server_name). Keeping the raw host around lets us
send a realistic SNI when the user passed a domain name, instead of a
hard-coded placeholder that fingerprints the protocol.