Instagram/IGListKit ? reverse-engineered prompt

Build me an iOS collection view library that makes it easy to show fast, flexible lists without me having to manually reload everything all the time.

I want it to be data driven, so I can give it my models and it figures out what changed and updates the screen smoothly. It should support multiple item types in the same list, reusable cells, and a clean way to plug in custom diffing for my own models. Please include a simple sample app so I can see how to use it in a real project, plus tests so the core behavior is reliable. It should work nicely with both Objective C and Swift, and be set up in a way that feels ready for a real production app, not just a demo.

If you need to, look up current docs online for the best modern iOS setup, but keep the main goal focused on a clean, easy way to build list based UIs.