VirtualList scroll position listener?

Flow
5

Equivalent in Java would be something like:

list1.getElement().addEventListener("scroll", e -> {
  list2.scrollToIndex(e.getEventData().get("event.target.firstVisibleIndex").intValue());
}).addEventData("event.target.firstVisibleIndex").debounce(200);

or

list1.getElement().addEventListener("scroll", e -> {
  list1.getElement().executeJs("return this.firstVisibleIndex").then(Integer.class, firstVisibleIndex -> {
    list2.scrollToIndex(firstVisibleIndex);
  });
}).debounce(200);

but the UX isn’t as nice as syncrhonizing on the client. You don’t want to be sending every scroll event to the server after all.