createRoute method
Creates the Route that corresponds to this page.
The created Route must have its Route.settings property set to this Page.
Implementation
@override
Route<T> createRoute(BuildContext context) {
return _PageBasedCupertinoSheetRoute<T>(
page: this,
scaleEffect: scaleEffect,
topSpace: topSpace,
barrierColor: scaleEffect ? Colors.transparent : Color(0x59000000),
);
}