Understanding Swift concurrency

In Swift 5.5, Apple added support for writing asynchronous and parallel code in a structured way.

Asynchronous code allows your app to suspend and resume code. This allows your app to do things like update the user interface while still performing operations like downloading data from the internet.

Parallel code allows your app to run multiple pieces of code simultaneously.

You can find links to all of Apple’s Swift concurrency videos during WWDC21 at https://developer.apple.com/news/?id=2o3euotz.

You can read Apple’s Swift concurrency documentation at https://developer.apple.com/news/?id=2o3euotz.

To give you an idea of how Swift concurrency works, imagine that you are making a poached egg sandwich for breakfast. Here is one way of doing it:

1. Put two slices of bread into the toaster.
2. Wait two minutes until the bread is toasted.
3. Put an egg in a bowl with some water and put the bowl...