convert widget to sliver

very often you have to convert the widget to slivers

@@ -47,3 +47,7 @@ extension WidgetMarginX on Widget {
 
 
   Widget get marginZero => Container(margin: EdgeInsets.zero, child: this);
   Widget get marginZero => Container(margin: EdgeInsets.zero, child: this);
 }
 }
+
+extension WidgetSliverBoxX on Widget {
+  sliverBox() => SliverToBoxAdapter(child: this);
+}