code: func (t *Torrent) startMissingTrackerScrapers() {
  	if t.cl.config.DisableTrackers {
  		return
  	}
  	t.startScrapingTracker(t.metainfo.Announce)
  	for _, tier := range t.metainfo.AnnounceList {
  		for _, url := range tier {
  			t.startScrapingTracker(url)
  		}
  	}
  }
docs: // Adds and starts tracker scrapers for tracker URLs that aren't already
  // running.