pub fn send_syn(collector: &Collector) -> Result<(), io::Error> {
    let (mut tx, _) = transport_channel(100, Layer3(Tcp)).unwrap();
    let mut packet = [0u8;40];
    let packet = build_pkt(collector, &mut packet);
    match tx.send_to(packet, IpAddr::V4(collector.dst_ip)) {
        Ok(_) => Ok(()),
        Err(e) => Err(e),
    }
}