await suspension point, why should we use it over locks ?

Using await suspension points in Swift over traditional locks offers several advantages, particularly in terms of performance and code clarity.

Efficiency: When a task is waiting for an asynchronous operation to complete, such as reading from a disk or waiting for a network response, it can suspend and yield the CPU to other tasks. This is more efficient than holding a lock, which can block other tasks from executing. The async/await model allows the system to manage task scheduling more effectively, improving overall performance.
Memory Management: Async functions in Swift manage their local state differently from synchronous functions. They use a separate stack and allocate memory in slabs, which can be more efficient than traditional stack allocation. This approach reduces the overhead associated with context switching and memory allocation, as described in the Explore Swift performance session.
Code Clarity: The async/await syntax makes the code easier to read and understand compared to using locks and callbacks. It clearly indicates where a function may suspend, making it easier to reason about the flow of asynchronous code.
Data Race Safety: Swift's concurrency model, including the use of actors and sendable types, helps prevent data races by ensuring that shared mutable state is accessed safely. This is a significant advantage over using locks, which require careful management to avoid deadlocks and race conditions. The Migrate your app to Swift 6 session discusses data-race safety in more detail.

Overall, using await suspension points aligns with Swift's goals of safety and performance, providing a modern approach to concurrency that reduces the complexity and potential pitfalls associated with traditional locking mechanisms.