Vaadin Push - only i window usecase

As of my understanding, vaadin push is set by adding anotation in UI class.
if the apps using only one UI class, mean the vaadin push is working for all the application.

How if the use case only on spesific screen or maybe only in one window ?
it would be nice if we can on/off the push, so the resources on serverside also getting more efficient.

sorry If I far from the architeture