async def postprocess(
        self, app: App, state: BaseState, event: Event, update: StateUpdate
    ) -> StateUpdate:
        """Postprocess the event.

        Args:
            app: The app.
            state: The client state.
            event: The event to postprocess.
            update: The current state update.

        Returns:
            An optional state to return.
        """
        return update
Postprocess the event.

        Args:
            app: The app.
            state: The client state.
            event: The event to postprocess.
            update: The current state update.

        Returns:
            An optional state to return.
        
reflex/middleware/middleware.py