Earlier quoted context omitted.
Title of this post: Mono for Unreal Engine
That may be the title of the post, but it doesn't reflect the real-world situation.
C# for Unreal Engine
With Mono for Unreal Engine, you can now use the latest version of C# to write your gameplay code, AI behaviors, UI elements, and more.
You have access to the entire range of capabilities of the .NET framework, up to version 4.5. You can even use C# async programming to author your code. Download it and give it a try.