code: func (ub *URLBuilder) cloneRoute(name string) clonedRoute {
  	route := new(mux.Route)
  	root := new(url.URL)
  
  	*route = *ub.router.GetRoute(name) // clone the route
  	*root = *ub.root
  
  	return clonedRoute{Route: route, root: root, relative: ub.relative}
  }
docs: // clondedRoute returns a clone of the named route from the router. Routes
  // must be cloned to avoid modifying them during url generation.