batch requests: Send a new request as soon as one is downloaded

[eliocamp]

The way the queue system is implemented now, once one requests is finished and downloaded, the code then checks the next request instead of immediately sending a new request. In practice requests will probably finish processing at roughly the same time, so the function will download one after the other until it stops and then send the new requests. It would be more time efficient to send a new request each time one is downloaded so it can start being processed while the code downloads the next.

I hope this is clear enough. 🤣