This patch refactors the result class to replace proxy results with the
possibility of doing data sharing through a shared heap allocated data
reference count. This is more robust and simpler since proxy results no
longer need to be handled as a special case in a lot of the results
code. Additionally, it allows stronger const correctness since inputs to
operations can now be const.
This is somewhat similar to implicit sharing used in other parts of
Blender, so we can look into using that in the future.
Pull Request: https://projects.blender.org/blender/blender/pulls/135778
b37afc86d1