webman里面直接输出phpspeadsheet导出的文件到php://output

    $writer = new Xlsx($spreadsheet);
    $response = response();
    ob_start();
    $writer->save('php://output');
    $c = ob_get_contents();
    ob_flush();
    flush();
    $response->withHeaders([
        'Content-Type' => 'application/vnd.ms-excel',
        'Content-Disposition' => 'attachment;filename="xxx.xlsx"',
        'Cache-Control' => 'max-age=0',
    ])->withBody($c);
    return $response;