Switch to not using streaming.

[Jjle1999]

I'm experiencing an excessive number of 429 errors reported when using the Gemini API, and I can almost confirm that the limit is not exceeded.

When I tried searching for this issue, I found someone mentioning that Gemini will be more prone to triggering 429 errors when streaming is turned on.

Therefore, I was hoping that a feature could be added to switch whether streaming is used or not.