Function handle_server_hello 

pub(super) fn handle_server_hello(
    cx: &mut Context<'_, ClientConnectionData>,
    server_hello: &ServerHelloPayload,
    randoms: ConnectionRandoms,
    suite: &'static Tls13CipherSuite,
    transcript: HandshakeHash,
    early_data_key_schedule: Option<KeyScheduleEarly>,
    our_key_share: Box<dyn ActiveKeyExchange>,
    server_hello_msg: &Message<'_>,
    ech_state: Option<EchState>,
    input: ClientHelloInput,
) -> Result<Box<dyn State<ClientConnectionData> + 'static>, Error>

early_data_key_schedule is Some if we sent the “early_data” extension to the server.