WPopup constructor
      
      WPopup({ 
    
    
- Key? key,
- required Widget button,
- required Widget popupBuilder(- BuildContext context,
- VoidCallback close
 
- required WPopupController controller,
Implementation
WPopup({
  super.key,
  required this.button,
  required this.popupBuilder,
  required this.controller,
}) {
  this.controller._myPopup ??= this;
}