useLatest Hook Solves Stale Closure Problem in React Async Callbacks

A common React bug occurs when async callbacks capture outdated state values due to JavaScript closures, causing issues like falsely marking unsaved content as 'saved'. The useLatest hook from @reactuses/core addresses this by maintaining a ref whose .current always holds the most recent rendered value, without triggering re-renders. Its implementation updates the ref inside a layout effect rather than during render, ensuring compatibility with React's concurrent rendering rules. The hook is useful across many async patterns including setTimeout, WebSocket handlers, and third-party SDK callbacks that outlive the render cycle that created them. Developers are advised to use both the closure value and the ref together — the closure for what was sent, and the ref for what the current state is at resolution time.