code: private function isCacheable($data)
      {
          $cacheable = true;
          array_walk_recursive($data, function ($value) use (&$cacheable) {
                  if ($value instanceof \Closure) {
                      $cacheable = false;
                  }
              });
  
          return $cacheable;
      }
docs: Ensures route data does not contain any Closures
  
  @return bool