fix: astream is not sending token in python 3.10

[riunyfir]

• Description:
  In Python 3.10, asynchronous generators may not yield control immediately after yield, causing the event loop to be unable to process other tasks in a timely manner and thus affecting the real-time performance of streaming transmission. Python 3.12 has optimized the behavior of asynchronous generators, so they function properly.
  When calling agent.astream() or similar asynchronous streaming methods, you won't receive each token in real-time. All tokens are returned at once after the message is fully generated. In Python 3.12, the same code can properly receive tokens one by one.
  The solution is to add await asyncio.sleep(0) after each yield statement in the asynchronous generator to explicitly yield control, ensuring that the event loop can process streaming data in a timely manner.
• **Issue:**Fixes astream is not sending token in python 3.10 #33903
• Dependencies: None

[ccurme]

The originating issue seems to relate to ChatOllama, why are we modifying langchain-openai here?

[parth-dobariya-hdrs]

hi @ccurme , i also observed that this issue #33907 is not provider specific , i tried with both ChatOllama and ChatGroq and the issue persisted in both providers .

[jgasparetti]

I tested ChatOllama and ChatOpenAI and both suffer of the same issue.