vsync property Null safety

TickerProvider? vsync
@Deprecated('Specify SliverPersistentHeaderDelegate.vsync instead. ' 'This feature was deprecated after v1.19.0.'), final

The TickerProvider for the AnimationController that causes a floating header to snap in or out of view.

Implementation

@Deprecated(
  'Specify SliverPersistentHeaderDelegate.vsync instead. '
  'This feature was deprecated after v1.19.0.',
)
final TickerProvider? vsync;