hmm, i'm not sure i'm parsing your suggestion. is "pop something out" something that i should try doing, or is it a possibility that i need to account for?
the goal is to compose `Render`able widgets inside the `render` method of other widgets
Collected::Box is for when they are ephemeral (owned by the render method) and Collected::Ref is for when they are stateful (owned by the parent struct), if that makes sense