A provider for both enter and exit animations of sub-containers of a PanelContainer. This provider will be bound to a SubContainerAnimationProviderContext that can be used to store information in a view model that survives configuration changes. For instance, it can store the PanelTransitionSource of the enter animation to later on use it to determine the exit animation.
Information for an SubContainerAnimationProvider of a PanelContainer about how it should provide its enter and exit animations. Can be created through PanelContainerContext.createAnimationProviderContext.