langchain/callbacks/manager.py/AsyncCallbackManagerForLLMRun/on_llm_end
class AsyncCallbackManagerForLLMRun:    async def on_llm_end(self, response: LLMResult, **kwargs: Any) -> None:
        """Run when LLM ends running."""
        await _ahandle_event(
            self.handlers,
            "on_llm_end",
            "ignore_llm",
            response,
            run_id=self.run_id,
            parent_run_id=self.parent_run_id,
            **kwargs,
        )