Similar to the non-streaming implementation, the InvokeStreamingAsync method only yields a streaming response when the OnIntermediateMessage callback is provided. Consider yielding the streaming response even if the callback is null to maintain consistency with previous behavior.

[Bryan-Roe]

Similar to the non-streaming implementation, the InvokeStreamingAsync method only yields a streaming response when the OnIntermediateMessage callback is provided. Consider yielding the streaming response even if the callback is null to maintain consistency with previous behavior.

Originally posted by @Copilot in #749 (comment)