Swift Concurrency

Lifecycle Position

Phase 3 (Implement) and Phase 5 (Review). Load for async patterns during implementation; use checklist during code review. Related: swift-networking for async network calls.

Decision Tree: Where Should This Code Run?

Is it UI code (views, view models, UI state)?
  → Yes → @MainActor
Does it manage shared mutable state?
  → Yes → Custom actor
Is it pure computation with no shared state?
  → Yes → nonisolated (Swift 6.2: @concurrent for CPU-heavy work)
Is it a one-off async operation from synchronous code?
  → Yes → Task { } (inherits actor context)