If anyone cares, I recently updated Swift version of Spine ESS runtime. This runtime is written on top of SpriteKit 2D engine (native framework from Apple). This runtime supports basically all Apple platforms (iOS, macOS, tvOS and watchOS).
If you crazy enough to make your game project native on a SpriteKit - welcome aboard!
Source code and documentation you can find here:
https://github.com/maxgribov/Spine