How to remove or hide the current snackbar in flutter with scaffoldkey?

Question

The below code works fine but doesn't hide snack bar on user signout. It invokes the code _scaffoldKey.currentState.hideCurrentSnackBar(); but doesn't hide the snackbar.

How to remove or hide the current snackbar?

class HomeScreen extends StatefulWidget {
  @override
  _HomeScreenState createState() => _HomeScreenState();
}

class _HomeScreenState extends State<HomeScreen>
    with AutomaticKeepAliveClientMixin {

  @override
  bool get wantKeepAlive => true;


@override
  Widget build(BuildContext context) {
    // need to call super method for AutomaticKeepAliveClientMixin
    super.build(context);

    print('Rebuild in Home Screen.....');

    return StreamBuilder<app.User>(
          stream: Provider.of<AuthProvider>(context, listen: true).user,
          builder: (context, snapshot) {
               return StreamBuilder<List<UserMovies>>(
                  stream: Provider.of<UserDetailsProvider>(context, listen: false)
                    .getUserFavouriteMovies(),
               builder: (context, snapshotMovies) {
                    Movies movies = snapshotMovies.hasData &&
                                snapshotMovies.data.length > 0
                            ? snapshotMovies.data[0]
                            : null;
  
                    _showSnackBar(context, movies);

                   return SizedBox(height: 2.0);
             },
         },
      ),
   }

  void _showSnackBar(BuildContext ctx, Movies movies) {
    if (movies == null) {
      _scaffoldKey.currentState.hideCurrentSnackBar();
    } else {
      WidgetsBinding.instance.addPostFrameCallback(
        (_) => {
          print('showCurrentSnackBar'),
          _scaffoldKey.currentState.showSnackBar(
            SnackBar(
              backgroundColor: Colors.deepPurple.shade300,
              content: Text("Hello World!"),       
              duration: const Duration(
                days: 1,
              ),
              behavior: SnackBarBehavior.floating,
              margin: EdgeInsets.zero,
              shape: const RoundedRectangleBorder(
                borderRadius: BorderRadius.all(
                  const Radius.circular(0.0),
                ),
              ),
            ),
          ),
        },
      );
    }
  }
}