Symfony-在我的csv文件中写入列

Question

我进行了api调用，该命令以csv格式从表中下载数据。但是，我的Csv中所有数据之前的第一行应该是表中所有列的名称，但是我找不到解决方案。有什么建议吗？

public function exportCSVAction()
{
    $results = $this->getDoctrine()->getManager()
        ->getRepository('ProjectBundle:User')->findAll();

    //$columns = ["id","username","email","first_name","last_name","address_one", "city","post_code","mobile","status"];

    $response = new StreamedResponse();
    $response->setCallback(function () use ($results) {
            $handle = fopen('php://output', 'r+');
        foreach ($results as $row) {
                $data = array(
                    $row->getId(),
                    $row->getUsername(),
                    $row->getEmail(),
                    $row->getFirstName(),
                    $row->getLastName(),
                    $row->getAddressOne(),
                    $row->getCity(),
                    $row->getPostCode(),
                    $row->getMobile(),
                    $row->getStatus(),
                );
                fputcsv($handle, $data);
            }
            fclose($handle);
        }
    );
    $response->headers->set('Content-Type', 'application/force-download');
    $response->headers->set('Content-Disposition', 'attachment; filename="export.csv"');

    return $response;
}