code: func (s *HTTPServer) parseDC(req *http.Request, dc *string) {
  	if other := req.URL.Query().Get("dc"); other != "" {
  		*dc = other
  	} else if *dc == "" {
  		*dc = s.agent.config.Datacenter
  	}
  }
docs: // parseDC is used to parse the ?dc query param