Swift Concurrency Async

Swift Concurrency is Apple's modern concurrency framework introduced in Swift 5.5 (iOS 15+). It includes async/await (for writing asynchronous code that reads sequentially), structured concurrency (tasks, task groups, cancellation), and actors (for safe mutable state in concurrent code). Unlike callbacks or Combine, async/await makes concurrent code read like synchronous code. Threads are managed automatically; developers focus on what to do, not how to manage threads.