Exit processing in httprl_send_request() after specified page request run time

For link checker module integration I need the ability to exit the httprl_send_request() process after a specified time. Everything not completed is no problem at all. Until _linkchecker_status_handling() has not been executed and updated a timestamp in the local database the link get selected again for check on next cron.

Use case:
0. Link checker check links via cron in a background task...
1. We can add 1.000 links to httprl_request()
2. After a limited time the check process need to be exited cleanly so, cron does not fail. Current implementation works this way:

    if ((timer_read('page') / 1000) > ($max_execution_time / 2)) {
      break; // Stop once we have used over half of the maximum execution time.
    }

Aside of this, are we able to add a callback function to httprl_send_request()? e.g. I need to call _linkchecker_status_handling($link, $response); after a link check has been completed. Today I would need to wait for all request results until httprl_request() has completed all checks and than the time to update all results in linkchecker_links table may not enough depending on the number of results. And than cron will be logged as crashed again :-(.