Build a Reliable Streaming Chat UI

You are building a React-based chat interface where responses stream into the UI token by token in real time. Before writing code, explain how you would approach building the feature. In your answer, cover: - What architecture and data flow you would use for live updates. - Two pieces of state that exist only while a stream is active and should be cleaned up after the stream finishes. - How to manage React state so streamed tokens do not flicker or overwrite existing content. - What can go wrong if multiple responses stream at the same time. - How to prevent race conditions between concurrent streams. - When you would use `useRef` versus `useState` in this scenario.