func main[] : i64
    let s: i64 = must(net.udp_listen?(net.pack_addr(127, 0, 0, 1), 8000))

    io.println("Listening on port 8000...")
    while true
        let pkt: net.UDPPacket = net.udp_receive(s, 60000)
        if pkt->size <= 0
            net.UDPPacket.free(pkt)
            continue

        net.udp_send_to(s, pkt->source_addr, pkt->data, pkt->size)
        net.UDPPacket.free(pkt)