Write modern Swift concurrency with async/await, Task, TaskGroup, actors, @MainActor, Sendable, AsyncSequence/AsyncStream, and Swift 6 strict data-race safety. Use when writing or refactoring asynchronous Swift code, fixing "data race"/"non-Sendable"/"actor-isolated" compiler errors, replacing completion handlers, running work off the main thread, or coordinating concurrent tasks on any Apple platform (iOS 26+, macOS 26+, watchOS 26+).
