Function spawn_channel_relay 

pub fn spawn_channel_relay<R, W, F, G>(
    channel_id: u32,
    read_half: R,
    write_half: W,
    on_data: F,
    on_close: G,
) -> Sender<Bytes>
where
    R: AsyncRead + Unpin + Send + 'static,
    W: AsyncWrite + Unpin + Send + 'static,
    F: Fn(u32, Bytes) -> bool + Send + 'static,
    G: Fn(u32) + Send + 'static,