Add function to search to an iterator

[gadomski]

Right now we only support "complete" searching ... we should add a function to search to an iterator.

Discussed in #147

^{Originally posted by betolink June 12, 2025}
For cases where the results could potentially be in the 100s of thousands of items, what would be the recommended way of using rustac? in the normal API we could iterate over pages and deal with them one at the time to help with the memory footprint, with rustac I see a search_to_arrow, would this be more memory efficient that getting the results with the normal search? I'm not sure if a Python generator for "lazy loading" the results would be possible with the current architecture.

Thanks for the help!!