Call Twilio Functions from iOS in Swift

A Twilio Function can be used to make web requests from an iOS application without having to maintain a server. In this tutorial, a simple hard-coded Pikachu joke is returned by a Twilio Function, which is then called from an iOS app using `URLSession`. The iOS app parses the response data as JSON and displays the first joke on a label. To test the function, the URL path of the function can be visited in a web browser to verify that it returns the expected output. This tutorial demonstrates how Twilio Functions can simplify mobile app development by abstracting away server-side complexities.