One needs to send 1 mln HTTP requests concurrently, in batches, and read the responses. No more than 100 requests at a time.

Which way will it be better, recommended, idiomatic?

    1. Send 100 ones, wait for them to finish, send another 100, wait for them to finish… and so on
    1. Send 100 ones. And then keep adding new ones into the pool as requests in the pool finish. “Done - add a new one. Done - add a new one”.