Swift Concurrency

Priority: P0 (CRITICAL)

Write Structured Async Code

• Async Functions: Mark with async and call with await.
• async let: Use async let for parallel execution when multiple tasks independent.
• Task Groups: Use withTaskGroup or withThrowingTaskGroup for spawning dynamic number of tasks.
• Error Handling: Combine with throws. Always handle CancellationError.

See implementation examples for parallel fetch with async let and Task Groups.

Isolate State with Actors

• Data Isolation: Use actor for shared mutable state to avoid data races.
• @MainActor: Annotate UI classes (Views, ViewModels) with @MainActor for main thread execution. Use MainActor.run { ... } for inline UI updates in async blocks.
• Global Actors: Use @GlobalActor for specific thread-bound resources.
• nonisolated: Use nonisolated for methods that don't access actor state to avoid unnecessary hops.