Modern Swift Concurrency on iOS - async/await, structured concurrency, Task and Task.detached, actor and @MainActor isolation, Sendable and Swift 6 strict concurrency, AsyncSequence/AsyncStream, TaskGroup, async let, and bridging callbacks with withCheckedContinuation. Use when writing async iOS code, fixing data races or off-main-thread UI updates, parallelizing work, wrapping delegate/completion-handler APIs, or consuming Kotlin suspend/Flow exposed as Swift async. For reactive Publisher/subscriber pipelines use combine-framework; for SwiftUI state use swiftui-observation; for the KMP bridge use kmp-ios-integration.
