While working on #115750, I was attempting to conditionally change the duration of the SnackBar animation, depending on whether the theme was Material 3 or not.

The Scaffold creates the animation controller for its snackbars in the ScaffoldMessengerState method showSnackBar():

 _snackBarController ??= SnackBar.createAnimationController(vsync: this)

(scaffold.dart)

createAnimationController is a static method of SnackBar:

  static AnimationController createAnimationController({ required TickerProvider vsync }) {
    return AnimationController(
      duration: _snackBarTransitionDuration,
      debugLabel: 'SnackBar',
      vsync: vsync,
    );
  }

(snack_bar.dart)

Ideally we could pass an optional useMaterial3 parameter to this method, and change the duration accordingly.

However, when running a Material 3 example (like snackbar.2.dart in the above mentioned PR) I can't seem to access a value of Theme.of(context).useMaterial3 = true from ScaffoldMessengerState, though I can from ScaffoldState.

Perhaps there's a trivial solution to this, but I need some insight from someone with more Scaffold familiarity.