State Models
============

SimpleAppState is based on immutable, deep-copied values.

However, some applications need to work with large,
mutable, or non-serializable objects such as
3D geometry, vector graphics, or engine-level data.

This section introduces alternative state models
that trade safety for performance and flexibility.

.. toctree::
   :maxdepth: 1

   ref_app_state
   ref_slot
   when_to_use_ref_state