Function handshake 

pub fn handshake<B>(
    connection: Connection,
    config: Config,
    executor: Executor,
) -> Result<(SendRequest<B>, Driver), Error>

Available on crate features http-backend and http and std only.

Prepare a client connection. The returned driver must be run concurrently.

Application data is sent only after handshake confirmation. The QUIC endpoint must negotiate h3 and allow at least three peer unidirectional streams.