我正在尝试使用symfony 4.3中的new mailer component发送邮件，但是如果尝试实现，则会收到以下异常：

试图调用类“ Symfony \ Component \ Mime \ Header \ Headers”中名为“ getall”的未定义方法。

堆栈跟踪：

Symfony\Component\Debug\Exception\UndefinedMethodException:
Attempted to call an undefined method named "getall" of class "Symfony\Component\Mime\Header\Headers".

  at vendor/symfony/mailer/DelayedSmtpEnvelope.php:76
  at Symfony\Component\Mailer\DelayedSmtpEnvelope::getRecipientsFromHeaders(object(Headers))
     (vendor/symfony/mailer/DelayedSmtpEnvelope.php:69)
  at Symfony\Component\Mailer\DelayedSmtpEnvelope->getRecipients()
     (vendor/symfony/mailer/Transport/AbstractTransport.php:75)
  at Symfony\Component\Mailer\Transport\AbstractTransport->send(object(Email),object(DelayedSmtpEnvelope))
     (vendor/symfony/mailer/Transport/Smtp/SmtpTransport.php:115)
  at Symfony\Component\Mailer\Transport\Smtp\SmtpTransport->send(object(Email),null)
     (vendor/symfony/mailer/Mailer.php:38)
  at Symfony\Component\Mailer\Mailer->send(object(Email))
     (src/Controller/TicketController.php:209)
  at App\Controller\TicketController->sendEmail('example@mail.com','example@mail.com',null)
     (src/Controller/TicketController.php:193)
  at App\Controller\TicketController->handleRequest(object(Request))
     (src/Controller/TicketController.php:51)
  at App\Controller\TicketController->createGeneral(object(Request))
     (vendor/symfony/http-kernel/HttpKernel.php:151)
  at Symfony\Component\HttpKernel\HttpKernel->handleRaw(object(Request),1)
     (vendor/symfony/http-kernel/HttpKernel.php:68)
  at Symfony\Component\HttpKernel\HttpKernel->handle(object(Request),1,true)
     (vendor/symfony/http-kernel/Kernel.php:198)
  at Symfony\Component\HttpKernel\Kernel->handle(object(Request))
     (index.php/:25)

到目前为止，我的代码：

use Symfony\Component\Mailer\Exception\TransportExceptionInterface;
use Symfony\Component\Mailer\MailerInterface;
use Symfony\Component\Mime\Email;

class TicketController extends AbstractController
    {
        private $mailer;
        public function __construct(MailerInterface $mailer)
        {
            $this->mailer = $mailer;
        }

    [...]

        public function sendEmail($ticketRecipient,$responsibilityRecipient)
        {
            $email = (new Email())
                ->from('exampleSender@mail.com')
                ->to($ticketRecipient,$responsibilityRecipient)
                ->subject('example subject')
                ->text('example text')
                ->html('<p>todo Twig Integration<p/>');

            try {
                $this->mailer->send($email);
            } catch (TransportExceptionInterface $e) {
            }
        }
    }

我想念什么吗？