pue_app_bar_data library Null safety


This is a data class for the appBar that is defined in the Pueprint widget. To use, descendant PuePage widgets of the Pueprint parent define the appBarData that should be shown on the page. Then, the PuePage calls the setState method in this class which changes the state. Finally the parent Pueprint is notified of this state and gets rebuilt with the new data via the appBarBuilder parameter.
Pass this into the appBar parameter of PuePage to completely remove the appBar for that specific page.