问无法流pdf:在使用wordpress时已经发送的标题

EN

include(WPtest_PLUGIN_PATH.'/admin/includes/dompdf/lib/html5lib/Parser.php');
include(WPtest_PLUGIN_PATH.'/admin/includes/dompdf/lib/php-font-lib/src/FontLib/Autoloader.php');
include(WPtest_PLUGIN_PATH.'/admin/includes/dompdf/lib/php-svg-lib/src/autoload.php');
include(WPtest_PLUGIN_PATH.'/admin/includes/dompdf/src/Autoloader.php');
Dompdf\Autoloader::register();

use Dompdf\Dompdf;

class WPtest_Save_PDF{

    //use Dompdf\Dompdf;
    function __construct(){
        add_shortcode( 'save_me',array($this,'print_callback'));
    }       


    function print_callback(){

        if(isset($_GET['print']))
        {


            $dompdf = new Dompdf();

            $dompdf->loadHtml("test");

            // (Optional) Setup the paper size and orientation
            $dompdf->setPaper('A4', 'landscape');

            // Render the HTML as PDF
            $dompdf->render();

            // Output the generated PDF to Browser
            $dompdf->stream();

            exit();
        }

    }
}

new WPtest_Save_PDF;