The documentation says how in theory it could happen, but all actual client software just does ALPN, which is a TLS feature to let you pick a different sub-protocol after connecting. Since it's a TLS feature you are obliged to use encryption.
The documentation says how in theory it could happen, but all actual client software just does ALPN, which is a TLS feature to let you pick a different sub-protocol after connecting. Since it's a TLS feature you are obliged to use encryption.