CustomScrollPhysics library Null safety

Classes

DummyHScrollPhysics
physisc class for snapping list use two class because of flutter not changing physics dynamically as stated her https://master-api.flutter.dev/flutter/widgets/Scrollable/physics.html "The physics can be changed dynamically, but new physics will only take effect if the class of the provided object changes. Merely constructing a new instance with a different configuration is insufficient to cause the physics to be reapplied"
DummyVScrollPhysics

Enums

DummyChangePhysics