如何使用symfony csvencoder并返回csv文件

Question

我看不到如何使用该库并实际上返回一个csv文件，我希望它可以自动打开，如果使用标头，它将返回一个空文件

 use Symfony\Component\Serializer\Serializer;
 use Symfony\Component\Serializer\Encoder\CsvEncoder;
 use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;

 class export { 

 public function index($data) { 

 header('Content-type: text/csv');

 $serializer = new Serializer([new ObjectNormalizer()], [new 
 CsvEncoder()]);

 // instantiation, when using it inside the Symfony framework
 $serializer = $container->get('serializer');

 // encoding contents in CSV format
return $serializer->encode($data, 'csv');
 }
}