Symfony\Component\HttpFoundation\Response::__toString PHP Method

    public function __toString()
    {
        return
            sprintf('HTTP/%s %s %s', $this->version, $this->statusCode, $this->statusText)."\r\n".
            $this->headers."\r\n".
            $this->getContent();
    }

 public function __toString()
 {
     $this->headers->set('Content-Length', strlen($this->getContent()));
     return parent::__toString();
 }