protected function removeHandle(RequestInterface $request)
    {
        if (isset($this->handles[$request])) {
            $handle = $this->handles[$request];
            unset($this->handles[$request]);
            unset($this->resourceHash[(int) $handle->getHandle()]);
            curl_multi_remove_handle($this->multiHandle, $handle->getHandle());
            $handle->close();
        }
    }