Add support for cancel streaming requests.

[Jerry Zhang]

Description of the feature request:

I'm wondering if it's possible to add support to cancel streaming requests

What problem are you trying to solve with this feature?

While streaming long responses from Gemini, users may want to cancel the streaming before it's completed.

Any other information you'd like to share?

This PR MacPaw/OpenAI#214 realizes a similar feature to cancel streaming.

[Kapil Shanbhag]

Can be an interesting feature 🤔!

[tisfeng]

We need this feature 👍

[Paul Beusterien]

Thanks for the feature request. We've added it to our backlog, but haven't yet scheduled it. In the meantime, please add your 👍 to indicate interest.