How to handoff animation for iOS developers?

I'm a designer and interested in different ways I can handoff animation to iOS developers and the best ways to do that depending on a particular case.

1. JSON

I know Lottie works best for animating micro-interactions and creating an animated illustration, like those on onboarding pages. For a designer, it's easy to provide JSON file since it can be generated with Bodymovin plugin in AfterEffects. The developer just gets the file and uses it as is, no more additional efforts for him.

2. Swift or Objective C

iOS has different animation API, like UIView so a developer can recreate animation from a video or designer can explain it in words. In this case, the developer has to code everything himself.

3. Export from design tools

Some design tools are able to export into Swift or Objective C. Flow is able to generate Swift code, Framer does it as well.

What are other technologies developers use to create animations?

What type of files, prototypes designers should provide for the developer considering different cases?