code: func (s *ProxyServer) ListenUnix(path string) (net.Listener, error) {
  	// Remove any socket, stale or not, but fall through for other files
  	fi, err := os.Stat(path)
  	if err == nil && (fi.Mode()&os.ModeSocket) != 0 {
  		os.Remove(path)
  	}
  	// Default to only user accessible socket, caller can open up later if desired
  	oldmask, _ := util.Umask(0077)
  	l, err := net.Listen("unix", path)
  	util.Umask(oldmask)
  	return l, err
  }
docs: // ListenUnix does net.Listen for a unix socket