code: func (d *KVGetQuery) Fetch(clients *ClientSet, opts *QueryOptions) (interface{}, *ResponseMetadata, error) {
  	select {
  	case <-d.stopCh:
  		return nil, nil, ErrStopped
  	default:
  	}
  
  	opts = opts.Merge(&QueryOptions{
  		Datacenter: d.dc,
  	})
  
  	log.Printf("[TRACE] %s: GET %s", d, &url.URL{
  		Path:     "/v1/kv/" + d.key,
  		RawQuery: opts.String(),
  	})
  
  	pair, qm, err := clients.Consul().KV().Get(d.key, opts.ToConsulOpts())
  	if err != nil {
  		return nil, nil, errors.Wrap(err, d.String())
  	}
  
  	rm := &ResponseMetadata{
  		LastIndex:   qm.LastIndex,
  		LastContact: qm.LastContact,
  		Block:       d.block,
  	}
  
  	if pair == nil {
  		log.Printf("[TRACE] %s: returned nil", d)
  		return nil, rm, nil
  	}
  
  	value := string(pair.Value)
  	log.Printf("[TRACE] %s: returned %q", d, value)
  	return value, rm, nil
  }
docs: // Fetch queries the Consul API defined by the given client.