能否增加返回结果的状态，类似langchain的Callbacks/Streaming tokens

[supercocoa]

Initial Checks

• [X] I have searched Google & GitHub for similar requests and couldn't find anything
• [X] I have read and followed the docs & demos and still think this feature is missing

Description

目前貌似无法区分哪些是action，哪些是最终可以返回的结果，看了下langchain里边有个callback用来区分就挺方便：on_tool_start / on_text / on_agent_action / on_agent_finish https://python.langchain.com/v0.1/docs/modules/callbacks/ langchain0.2里好像还加了个Streaming tokens用来区分 event["event"] == "on_tool_start" https://python.langchain.com/v0.2/docs/tutorials/agents/#streaming-tokens

Use case

No response

[zzhangpurdue]

好的，我们尽快调研支持一下