How to integrate Unity into a Swift 3 iOS project

Question

I was just wondering what might be the best strategy for implementing a Unity project into a already existing Swift 3 iOS project. So far I only discovered sample code in Ob

Answer 1

The tutorial mentioned in the accepted answer is a good step by step guide to integrate Unity to Swift project.

However, there are couple of changes needed for Swift 4 and Unity 2017.1. Here is a demo project in case someone needs it.