- Add a custom Iterator, so it can be iterated as a 1D list.
- Add missing functions like `first`, `is_empty`, `clear`, and
subscript operator.
- Add a `size_` member variable for faster `size` calls.
- Add compile-time asserts to ensure the Capacity sizes are valid.
- Add unit tests.
See #138947 for the motivation behind this.
Pull Request: https://projects.blender.org/blender/blender/pulls/139102
4f00a470cd