airbnb/lottie-ios ? reverse-engineered prompt

Build me an iOS animation library that can take vector animations exported from After Effects as JSON and render them smoothly in real time inside an app.

I want it to feel easy for designers and developers to use, so the app should be able to load animations, play them, loop them, resize them, speed them up or slow them down, reverse them, and scrub through them interactively. It should also let me play only part of an animation if I want, and change things like color or position at runtime without having to rebuild the animation from scratch.

Please include a small example app where I can browse through a bunch of sample animations and test how they look. Make sure it works cleanly with current iOS tooling, and if you need to check the latest docs for anything, look them up online.