Hey friend, I think I found a smol bug. the streaming flag in llama index's base query class checks to make sure the model is an OpenAI model. This is intentional, but it breaks when a ChatOpenAI instance is used. LangChain supports streaming functionality for ChatOpenAI, but it's getting blocked by the instance check in line 246 of llama_index/llm_predictor/base.py
~/.local/lib/python3.9/site-packages/llama_index/llm_predictor/base.py in stream(self, prompt, **prompt_args)
245 """
246 if not isinstance(self._llm, OpenAI):
--> 247 raise ValueError("stream is only supported for OpenAI LLMs")
248 formatted_prompt = prompt.format(llm=self._llm, **prompt_args)
249 raw_response_gen = self._llm.stream(formatted_prompt)
ValueError: stream is only supported for OpenAI LLMs