message: UDP association socket shouldn't bind local_address
  ref
diff: @@ -636,16 +636,8 @@ impl ServerAssociation {
  mut response_tx: mpsc::Sender<(SocketAddr, BytesMut)>,
  ) -> io::Result<ServerAssociation> {
  // Create a socket for receiving packets
  - let local_addr = match context.config().local_addr {
  - None => {
  - // Let system allocate an address for us
  - SocketAddr::new(IpAddr::V4(Ipv4Addr::new(0, 0, 0, 0)), 0)
  - }
  - Some(ref addr) => {
  - // Uses configured local address
  - addr.bind_addr(&context).await?
  - }
  - };
  + // Let system allocate an address for us (INADDR_ANY)
  + let local_addr = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(0, 0, 0, 0)), 0);
  let remote_udp = create_udp_socket(&local_addr).await?;
  let local_addr = remote_udp.local_addr().expect("could not determine port bound to");
  