强制下载tar.xz导致php中的文件损坏

IF i download filename.tra.xz it courrupted.

$newfile=$row['orginal_filename']; //download file name
$download_file='Attachment/'.$row['path'];
header('Content-type: application/x-gzip');
//header("Content-Type: application/forcedownload");
header("Content-Length: " . filesize($download_file));
header('Content-Disposition: attachment; filename="' . $newfile . '"');
readfile($download_file);
exit();