Swift 5's Result Type

Before Swift 5 we used to write our own Result type to contain a value or an error (but never both). A lot of 3rd party libraries brought along their own as well. Then Swift 5 came and brought us Result. Not only is it slightly different than the ones we might be familiar with, Swift's Result type also has some useful functionality up its sleeve.

This is a companion discussion topic for the original entry at https://nsscreencast.com/episodes/417-swift-5-result-type