Async issue streams don't utilize next page tokens

[ericyanush]

First off, thanks to all the maintainers of this project for the quick response/updates that were made to support the V3 search APIs! Your efforts are greatly appreciated!

It seems that the V3 next_page_token is now used correctly in the synchronous iter() API, however it appears that the async APIs try to use the V2 pagination scheme, which results in a never ending search result set. While this functionality can be manually implemented using the new next_page_token() method on the SearchOptionsBuilder, it appears that the intention was to keep that method "internal".

[avrabe]

Fixed in v0.15.1! 🎉

The async stream was creating new futures on each poll, losing pagination state. Added persistent fetch_future field to maintain state across polls.

What we missed in testing:

• No multi-page async stream tests
• No V3 nextPageToken validation
• No timeout guards for infinite loops

Added comprehensive V3 pagination tests in tests/v3_pagination_test.rs.

Available now on crates.io and GitHub.

Thanks for the excellent bug report!