Previously retrieving a collection from the context like "selected_ids"
would give a linked list of allocated items. Now it returns a vector of
RNA pointers. Though the number of items is typically fairly small,
using contiguous memory and avoiding many small allocations are
typical performance improvements that could still be beneficial
when there are many items. Iteration also becomes much simpler.
Pull Request: https://projects.blender.org/blender/blender/pulls/119939
acd1b0b7f9