code: func NeighSubscribeWithOptions(ch chan<- NeighUpdate, done <-chan struct{}, options NeighSubscribeOptions) error {
  	if options.Namespace == nil {
  		none := netns.None()
  		options.Namespace = &none
  	}
  	return neighSubscribeAt(*options.Namespace, netns.None(), ch, done, options.ErrorCallback, options.ListExisting)
  }
docs: // NeighSubscribeWithOptions work like NeighSubscribe but enable to
  // provide additional options to modify the behavior. Currently, the
  // namespace can be provided as well as an error callback.