code: func (me *trackerScraper) announce() (ret trackerAnnounceResult) {
  	defer func() {
  		ret.Completed = time.Now()
  	}()
  	ret.Interval = 5 * time.Minute
  	ip, err := me.getIp()
  	if err != nil {
  		ret.Err = fmt.Errorf("error getting ip: %s", err)
  		return
  	}
  	me.t.cl.lock()
  	req := me.t.announceRequest()
  	me.t.cl.unlock()
  	res, err := tracker.Announce{
  		HTTPProxy:  me.t.cl.config.HTTPProxy,
  		UserAgent:  me.t.cl.config.HTTPUserAgent,
  		TrackerUrl: me.trackerUrl(ip),
  		Request:    req,
  		HostHeader: me.u.Host,
  		ServerName: me.u.Hostname(),
  		UdpNetwork: me.u.Scheme,
  		ClientIp4:  krpc.NodeAddr{IP: me.t.cl.config.PublicIp4},
  		ClientIp6:  krpc.NodeAddr{IP: me.t.cl.config.PublicIp6},
  	}.Do()
  	if err != nil {
  		ret.Err = fmt.Errorf("error announcing: %s", err)
  		return
  	}
  	me.t.AddPeers(Peers(nil).AppendFromTracker(res.Peers))
  	ret.NumPeers = len(res.Peers)
  	ret.Interval = time.Duration(res.Interval) * time.Second
  	return
  }
docs: // Return how long to wait before trying again. For most errors, we return 5
  // minutes, a relatively quick turn around for DNS changes.