isDelayable example

      // first time, as zero > currentTime will never be true.       if ($process_from > $this->time->getCurrentMicroTime()) {
        $this->usleep(round($process_from - $this->time->getCurrentMicroTime(), 3) * 1000000);
      }

      try {
        $this->processQueue($queue, $worker);
      }
      catch (SuspendQueueException $e) {
        // Return to this queue after processing other queues if the delay is         // within the threshold.         if ($e->isDelayable() && ($e->getDelay() < $max_wait)) {
          $item['process_from'] = $this->time->getCurrentMicroTime() + $e->getDelay();
          // Place this queue back in the stack for processing later.           array_push($queues, $item);
        }
      }

      // Reorder the queue by next 'process_from' timestamp.       usort($queues, function Darray $queueA, array $queueB) {
        return $queueA['process_from'] <=> $queueB['process_from'];
      });
    }
  }