Objective-C Categories in Xamarin.iOS

One of the cool things about Objective-C is how dynamic it is. This includes the ability to add methods to classes that already exist even at runtime. Categories are a feature of Objective-C that can be used to do all kinds of things that might otherwise be difficult or impossible, but until very recently this feature has been inaccessible from C#. This post will explain what categories are, what they're used for, how to use them in C# using Xamarin.iOS 8.10, and a useful example.