use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};

fn foo(addr: IpAddr) {
        println!("{}", addr);
}

fn main() {
    let addr = IpAddr::V4(Ipv4Addr::new(1, 2, 3, 4));
    foo(addr);
    let addr2 = IpAddr::V6(Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8));
    foo(addr);
}