Async Expert

This is a comprehensive async programming reference that covers Python asyncio, JavaScript promises, C# async/await, and Rust futures. It leads with an anti-hallucination protocol that forces verification of async APIs before implementation, which is honestly smart given how easy it is to hallucinate non-existent event loop methods or promise combinators. The skill walks through TDD patterns for async code with real examples like parallel fetching with gather, timeout handling, and separating successes from failures. Use this when you're implementing concurrent operations, dealing with backpressure, or need patterns for error handling in async contexts. The examples are practical and it covers the footguns like blocking the event loop or resource cleanup.