Async

The concept of async/await in Swift is covered in several sessions at WWDC 2024. Here are some key points and relevant sessions:

1. A Swift Tour: Explore Swift’s features and design

   • This session explains how Swift uses the async and await keywords to handle asynchronous operations. When a task is waiting for an asynchronous operation to complete, it suspends to yield the CPU to other tasks. This is demonstrated with an example of building a server using the Hummingbird framework.
   • Concurrency

2. Migrate your app to Swift 6

   • This session discusses how to handle shared mutable state and data races in Swift 6. It explains that calls to actor-isolated state are implicitly asynchronous and how to use await to access global variables on the main actor.
   • Shared mutable state in global instances and functions

3. Go further with Swift Testing

   • This session covers how to test asynchronous code in Swift. It mentions that for most completion handlers, Swift provides an async overload that can be used instead. If an async overload is not available, you can use withCheckedContinuation or withCheckedThrowingContinuation to convert it to an expression that can be awaited.
   • Asynchronous conditions

4. Explore Swift performance

   • This session delves into the performance aspects of async functions. It explains how async functions are split into multiple partial functions at runtime and how memory allocation works for async tasks.
   • Async functions

These sessions provide a comprehensive overview of how async/await is implemented and used in Swift, along with practical examples and performance considerations.