anchor.diff:  ///    app. A bottom sheet can either be persistent, in which case it is shown
   ///    using the [ScaffoldState.showBottomSheet] method, or modal, in which case
   ///    it is shown using the [showModalBottomSheet] function.
  +///  * [SnackBar], which is a lightweight message with an optional action which
  +///    briefly displays at the bottom of the screen. Use the
  +///    [ScaffoldMessengerState.showSnackBar] method to show snack bars.
  +///  * [MaterialBanner], which displays an important, succinct message, at the
  +///    top of the screen, below the app bar. Use the
  +///    [ScaffoldMessengerState.showMaterialBanner] method to show material banners.
   ///  * [ScaffoldState], which is the state associated with this widget.
   ///  * <https://material.io/design/layout/responsive-layout-grid.html>
   ///  * Cookbook: [Add a Drawer to a screen](https://flutter.dev/docs/cookbook/design/drawer)
  
positive.code: 
    // SNACKBAR API
  
    /// Shows a [SnackBar] across all registered [Scaffold]s.
    ///
    /// A scaffold can show at most one snack bar at a time. If this function is
    /// called while another snack bar is already visible, the given snack bar
  
negative.code: 
    // MATERIAL BANNER API
  
    /// Shows a [MaterialBanner] across all registered [Scaffold]s. Scaffolds register
    /// to receive material banners from their closest [ScaffoldMessenger] ancestor.
    /// If there are several registered scaffolds the material banner is shown
    /// simultaneously on all of them.
    ///
    /// A scaffold can show at most one material banner at a time. If this function is
    /// called while another material banner is already visible, the given material banner
  