Downloading using closures

So, let's start with some of the simpler stuff, although we'll be cutting no corners. Firstly, we'll set up a local server onto which we can easily upload data, and then we'll go through some examples of using URLSession, starting with the simplest HTTP requests and then progressing to more customized solutions.

Starting a local test server on your machine

Before we write the Swift code to make our HTTP requests, we'll need something to send those requests to. Rather than us putting some example resources somewhere on the Web at which you can point your code, wouldn't it be much more satisfying to be able to quickly and simply start up a local server on your own machine that will host anything and everything...