async stream

Async Stream in Swift

In Swift, asynchronous functions and streams are implemented using the async and await keywords. Here are some key points about how async functions work in Swift:

1. Async Functions and Suspension Points:

   • Async functions are split into multiple partial functions at runtime, each spanning the gaps between potential suspension points (e.g., await calls).
   • When an async function is called, it may suspend at an await point, yielding the CPU to other tasks. This is crucial for efficient concurrency.

2. Memory Allocation for Async Functions:

   • Async functions do not allocate memory on the C stack. Instead, they use a separate stack, allocating memory in slabs.
   • When an async function needs memory, it requests it from the current slab. If the slab is full, a new slab is allocated using malloc.

3. Partial Functions:

   • Each async function is divided into partial functions. For example, if there is one await in the function, it results in two partial functions.
   • The first partial function runs until the await point, and the second one resumes after the await.

4. Concurrency and Task Suspension:

   • Swift uses the async keyword to mark functions that may suspend, and the await keyword to indicate suspension points.
   • This allows the CPU to be used efficiently by other tasks while waiting for asynchronous operations to complete.

For a detailed explanation of async functions and their implementation, you can refer to the session Explore Swift performance.

Relevant Sessions

1. Explore Swift performance
2. A Swift Tour: Explore Swift’s features and design
3. Explore the Swift on Server ecosystem
4. Go further with Swift Testing

These sessions cover various aspects of async functions, concurrency, and their applications in Swift.