Add @objc annotation for main classes and functions.

[7va]

Hello!

While Swift is generally considered to be a superior option, it may still be necessary to maintain compatibility with older projects written in Obj-C, Unity-generated projects, and KMM. To achieve this, it would be advisable to annotate all public classes and functions with the @objc annotation.

[antonselyanin]

Unfortunately, you can't just add @objc annotations to public APIs and achieve Objective C compatibility. It doesn't work with Swift structs, for instance.

In my opinion, a better way would be to wrap the existing API with objc-compatible layer, preferably as a separate package/library.