code: func (s *ReindexService) buildURL() (string, url.Values, error) {
  	// Build URL path
  	path := "/_reindex"
  
  	// Add query string parameters
  	params := url.Values{}
  	if s.pretty {
  		params.Set("pretty", "true")
  	}
  	if s.refresh != "" {
  		params.Set("refresh", s.refresh)
  	}
  	if s.timeout != "" {
  		params.Set("timeout", s.timeout)
  	}
  	if s.requestsPerSecond != nil {
  		params.Set("requests_per_second", fmt.Sprintf("%v", *s.requestsPerSecond))
  	}
  	if s.slices != nil {
  		params.Set("slices", fmt.Sprintf("%v", s.slices))
  	}
  	if s.waitForActiveShards != "" {
  		params.Set("wait_for_active_shards", s.waitForActiveShards)
  	}
  	if s.waitForCompletion != nil {
  		params.Set("wait_for_completion", fmt.Sprintf("%v", *s.waitForCompletion))
  	}
  	return path, params, nil
  }
docs: // buildURL builds the URL for the operation.