Question About Multiple Window Applications

In the Book of Vaadin, in Chapter 11, it states that “The example uses an invisible ProgressIndicator to implement polling. This is sort of a trick and a more proper API for polling is under design”

I understand what is going on here, but was wondering whether the “more proper API” has been completed.

A more proper API has been waiting to be implemented in the backlog for a long time (polling would be trivial to add, but it would be great to be able to have the API to support server push also).

Meanwhile, there is a bit more sane way of enabling polling with
refresher add-on