[Enhancement]:llm('hello')这样调用会执行langchain中LLM类的_call()方法，但是它只能return 一个str类型

[CyanMystery]

What would you like to be added?

我想它应该支持流式输出 使用yield返回，因此，处理llm('hello')这样调用之外，最好能使用llm.custom_func()调用

Why is this needed?

支持流式输出

Anything else?

No response

[SimFG]

@jiangbossB It's a great advice!

[SimFG]

If you want to support streaming output, this should be supported in langchain, such as returning a generator