Swiftui Guideline: Async — Use .task for async work. Description: Automatic cancellation on view disappear. Do: .task for view lifecycle async. Don't: onAppear with Task. Good Example: .task { await loadData() }. Bad Example: onAppear { Task { await loadData() } }. Severity: Medium. Docs: https://developer.apple.com/documentation/swiftui/view/task(priority:_:).