And now, the hard part: XML Parsing. The XMLParser API provided by the iOS SDK is an event-driven parser, and not particularly pleasant to work with, so we roll up our sleeves and dig in. We make our own parser class implement the XMLParserDelegate class, so it can be called back when the XMLParser starts and ends tags, finds text, and so on. By selectively handling these callbacks, we can parse the feed's top-level metadata into a Swift struct.
More info at the book's home page: pragprog.com/book/adios4/ios-10-sdk-development