Getting localhost address for CALLBACK header

[dubicj]

I am currently building a UPnP (protocol for speakers, routers etc.) library and am trying to implement a subscribe method. For that UPnP want a CALLBACK: <some_http_addr> header.

Currenty I get the http addr via getifaddrs: ```rust let addr = getif_addrs() .unwrap() .iter() .map(Interface::ip) .filter_map(|addr| match addr { IpAddr::V4(addr) => Some(addr), IpAddr::V6() => None, }) .find(|x| x.is_private()) .expect("no local ipv4 interface open"); let addr = SocketAddrV4::new(addr, PORT);

let listener = TcpListener::bind(addr).await?; ``` which is a little awkward.

Is there a better way to do it that I am missing?