message: Signal that watcher subscribers should clear their caches
diff: @@ -49,6 +49,10 @@ pub enum WatcherEvent<K> {
  /// NOTE: This should not be used for managing persistent state elsewhere, since
  /// events may be lost if the watcher is unavailable. Use Finalizers instead.
  Deleted(K),
  + /// The watch stream was restarted, so `Deleted` events may have been missed
  + ///
  + /// Should be used as a signal to clear caches.
  + Restarted,
  }
  #[derive(Derivative)]
  @@ -152,7 +156,7 @@ impl<K: Sync + Send + Meta + Clone + DeserializeOwned + 'static> Stream for Watc
  this.list_params.clone(),
  )),
  };
  - self.poll_next(cx)
  + Poll::Ready(Some(Ok(WatcherEvent::Restarted)))
  }
  State::InitListing { list_fut } => match list_fut.as_mut().poll(cx) {
  Poll::Pending => Poll::Pending,
  