src/SPLQueuePool.php
public function clear()
    {
        // clear free queue
        while ($obj = $this->getFreeQueue()->pop()) {
            $this->destroy($obj);
        }

        $this->busyQueue->removeAll($this->busyQueue);

        $this->freeQueue = null;
        $this->busyQueue = null;
    }
public function clear()
    {
        // clear free queue
        while ($obj = $this->getFreeQueue()->pop()) {
            $this->destroy($obj);
        }

        $this->busyQueue->removeAll($this->busyQueue);

        $this->freeQueue = null;
        $this->busyQueue = null;
    }
release pool