private function releaseMultiHandle($handle, $maxHandles)
    {
        $id = (int) $handle;

        if (count($this->multiHandles) <= $maxHandles) {
            $this->multiOwned[$id] = false;
        } elseif (isset($this->multiHandles[$id], $this->multiOwned[$id])) {
            // Prune excessive handles
            curl_multi_close($this->multiHandles[$id]);
            unset($this->multiHandles[$id], $this->multiOwned[$id]);
        }
    }