This swift library can be integrated into any Xcode project to easily keep track of time. It's quick and easy to use. http://kirankunigiri.com/Swift-Stopwatch-Library/
Clone the project and open it. There, you'll find a demo of the Stopwatch and some lovely documentation that you can read. All you need to do next is add the Stopwatch.swift file into your project and start using it!
This small project was created by Kiran Kunigiri