Function encode_server_request 

pub async fn encode_server_request<S, B, F, E>(
    req: Request<()>,
    stream_id: u64,
    stream: &mut RequestStream<S, B>,
    emit: F,
) -> Result<(), StreamEncodeError<E>>
where
    S: RecvStream,
    B: Buf,
    F: FnMut(StreamFrame) -> Result<(), E>,