Fix StateError

✅ Solution

The StateError "Cannot add new events after calling close" usually means you're trying to add data to a stream (like a StreamController) after it's been closed. Ensure you're not calling `sink.add()` or related stream operations after `close()` has been invoked on the StreamController. A common fix is to make sure to check `!streamController.isClosed` before attempting to add any new data or events.