Provide a refresh() method to override on page refresh (F5)

[zanonmark]

In Vaadin 7-8, we could override the refresh() method which was invoked when a UI was annotated with @PreserveOnRefresh and a manual refresh (e.g.: F5) was fired to the page.

Vaadin14 is missing such a feature.
Listening to a AfterNavigationEvent is not useful if you run a single-view page, because routing is not involved in this case.

Thanks,
MZ

[TatuLund]

I wonder why this ticket is still open as there is

    @Override
    public void afterNavigation(AfterNavigationEvent event) {
        if (event.isRefreshEvent()) {
           // Do the refresh stuff
        }
     }

[mcollovati]

Good catch @TatuLund.
This issue has been fixed by #15324, but it has not been back-ported to Vaadin 14.
@mshabarov do you think we can close it anyway?