$client = HttpClient::create();
$monitor = new ResponseSetMonitor($client);
$monitor->add($client->request(...), $onHeaders, $onBody, $onError);
// [...]
$monitor->tick(); // non-blocking call
// [...]
$monitor->tick(0.001); // don't make the tick last more than 1ms
// [...]
$monitor->complete(); // complete responses and consider timeouts as errors
// [...]
$monitor->cancel() // cancel all pending responses - usually run after a ->tick($someTimeout)