code: func (nc *Conn) shufflePool() {
  	if len(nc.srvPool) <= 1 {
  		return
  	}
  	source := rand.NewSource(time.Now().UnixNano())
  	r := rand.New(source)
  	for i := range nc.srvPool {
  		j := r.Intn(i + 1)
  		nc.srvPool[i], nc.srvPool[j] = nc.srvPool[j], nc.srvPool[i]
  	}
  }
docs: // shufflePool swaps randomly elements in the server pool