use Box\Spout\Writer\Common\Creator\WriterEntityFactory;
use Box\Spout\Common\Entity\Row;
$filePath = './test.xlsx';
$writer = WriterEntityFactory::createXLSXWriter();
// $writer = WriterEntityFactory::createODSWriter();
// $writer = WriterEntityFactory::createCSVWriter();
$start= mktime(true);
$writer->openToFile($filePath); // write data to a file or to a PHP stream
//$writer->openToBrowser($fileName); // stream data directly to the browser
$cells = [];
for($i =0;$i<50;$i++) {
    $cells[] =   WriterEntityFactory::createCell('Carl'.$i);
}

/** add multiple rows at a time */
$multipleRows = [];
for($z=0;$z<10000;$z++) {
 $multipleRows[] = WriterEntityFactory::createRow($cells);
}
$writer->addRows($multipleRows);
$writer->close();
$end= mktime(true);
echo $end-$start;