A library that provides dual-stack tokio sockets for use in [rqbit](https://github.com/ikatson/rqbit) torrent client.
It converts between SocketAddr addresses so that your app sees IPv4 (not IPv4-mapped IPv6) addresses.
If you listen on IPv6::UNSPECIFIED, it will enter dualstack mode (if requested) and listen on both IPv4 and IPv6. However all addresses will be converted
to their canonical form.