webman 怎么返回文件二进制流到客户端

$fp = fopen(...);
ob_start();
...
fclose(...);
$content = ob_get_clean();
return response($content, 200, [
    'Content-Description' => 'File Transfer',
    'Content-Type => 'application/vnd.ms-execl',
    // 其它header.....
]);