concurrency

Comprehensive concurrency and parallelism patterns for multi-threaded and async programming. Use when implementing async/await, parallel processing, thread safety, worker pools, or debugging race conditions and deadlocks. Triggers: async, await, thread, mutex, lock, semaphore, channel, actor, parallel, concurrent, race condition, deadlock, livelock, atomic, futures, promises, tokio, asyncio, goroutine, spawn, Arc, Mutex, RwLock, mpsc, select, join, worker pool, queue, synchronization, critical section, context switch.