code: func (s *RoundStrategy) Apply(nodes []Node) Node {
  	if len(nodes) == 0 {
  		return Node{}
  	}
  
  	n := atomic.AddUint64(&s.counter, 1) - 1
  	return nodes[int(n%uint64(len(nodes)))]
  }
docs: // Apply applies the round-robin strategy for the nodes.