* custom_sliver.dart class CustomSliver extends StatefulWidget { final Widget header; final Widget body; double? headerHeight; final bool automaticallyImplyLeading; CustomSliver({ Key? key, required this.header, required this.body, this.automaticallyImplyLeading = true, this.headerHeight, }) : super(key: key); @override _CustomSliverState createState() => _CustomSliverState(); } class _CustomSli..