code: func (r *PEXReactor) ensurePeersRoutine() {
  	// Randomize when routine starts
  	ensurePeersPeriodMs := r.ensurePeersPeriod.Nanoseconds() / 1e6
  	time.Sleep(time.Duration(rand.Int63n(ensurePeersPeriodMs)) * time.Millisecond)
  
  	// fire once immediately.
  	r.ensurePeers()
  
  	// fire periodically
  	ticker := time.NewTicker(r.ensurePeersPeriod)
  
  	for {
  		select {
  		case <-ticker.C:
  			r.ensurePeers()
  		case <-r.Quit:
  			ticker.Stop()
  			return
  		}
  	}
  }
docs: // Ensures that sufficient peers are connected. (continuous)