anchor.diff:  
   class _InheritedResetNotifier extends InheritedNotifier<_ResetNotifier> {
     /// Creates an [InheritedNotifier] that the [DraggableScrollableSheet] will
  -  /// listen to for an indication that it should change its extent.
  +  /// listen to for an indication that it should reset itself back to [DraggableScrollableSheet.initialChildSize].
     ///
     /// The [child] and [notifier] properties must not be null.
     const _InheritedResetNotifier({
  
positive.code:   bool get _isAtSnapSize {
      return extent.snapSizes.any(
        (double snapSize) {
          return (extent.currentExtent - snapSize).abs() <= extent.pixelsToExtent(physics.tolerance.distance);
        },
      );
    }
  
negative.code:   void _replaceExtent() {
      _extent.dispose();
      _extent = _extent.copyWith(
        minSize: widget.minChildSize,
        maxSize: widget.maxChildSize,
        snap: widget.snap,
        snapSizes: _impliedSnapSizes(),
        initialSize: widget.initialChildSize,
        onSizeChanged: _setSize,
      );
      // Modify the existing scroll controller instead of replacing it so that
      // developers listening to the controller do not have to rebuild their listeners.
  