allowSnapshotting property Null safety
Whether the route transition will prefer to animate a snapshot of the entering/exiting routes.
When this value is true, certain route transitions (such as the Android zoom page transition) will snapshot the entering and exiting routes. These snapshots are then animated in place of the underlying widgets to improve performance of the transition.
Generally this means that animations that occur on the entering/exiting route while the route animation plays may appear frozen - unless they are a hero animation or something that is drawn in a separate overlay.
@override bool get allowSnapshotting => false;