async def _arun_step(
        self, state: Dict[str, Any], task: Task, input: Optional[str] = None
    ) -> Tuple[AgentChatResponse, bool]:
        """
        Run step (async).

        Can override this method if you want to run the step asynchronously.

        Returns:
            Tuple of (agent_response, is_done)

        """
        raise NotImplementedError(
            "This agent does not support async.Please implement _arun_step."
        )

        Run step (async).

        Can override this method if you want to run the step asynchronously.

        Returns:
            Tuple of (agent_response, is_done)

        
llama-index-core/llama_index/core/agent/custom/simple.py