Agent Skills: concurrency-patterns

Expert Swift concurrency decisions: async let vs TaskGroup selection, actor isolation boundaries, @MainActor placement strategies, Sendable conformance judgment calls, and structured vs unstructured task trade-offs. Use when designing concurrent code, debugging data races, or choosing between concurrency patterns. Trigger keywords: async, await, actor, Task, TaskGroup, @MainActor, Sendable, concurrency, data race, isolation, structured concurrency, continuation