code: func (d *CatalogServicesQuery) 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/catalog/services",
  		RawQuery: opts.String(),
  	})
  
  	entries, qm, err := clients.Consul().Catalog().Services(opts.ToConsulOpts())
  	if err != nil {
  		return nil, nil, errors.Wrap(err, d.String())
  	}
  
  	log.Printf("[TRACE] %s: returned %d results", d, len(entries))
  
  	var catalogServices []*CatalogSnippet
  	for name, tags := range entries {
  		catalogServices = append(catalogServices, &CatalogSnippet{
  			Name: name,
  			Tags: ServiceTags(deepCopyAndSortTags(tags)),
  		})
  	}
  
  	sort.Stable(ByName(catalogServices))
  
  	rm := &ResponseMetadata{
  		LastIndex:   qm.LastIndex,
  		LastContact: qm.LastContact,
  	}
  
  	return catalogServices, rm, nil
  }
docs: // Fetch queries the Consul API defined by the given client and returns a slice
  // of CatalogService objects.