pub fn poll_send(&self, addr: &Address, payload: &[u8], cx: &mut Context<'_>) -> Poll<ProxySocketResult<usize>> {
        self.poll_send_with_ctrl(addr, &DEFAULT_SOCKET_CONTROL, payload, cx)
    }
poll family functions

Send a UDP packet to addr through proxy

NOTE: the `send_timeout` is ignored.
crates/shadowsocks/src/relay/udprelay/proxy_socket.rs