epub在成功下载后损坏

Question

I have a code:

$name = "jeffrey.epub"; //for naming only
$file = "test/cover/cabang.epub"; //the real file to be downloaded
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="'.basename($name).'"');
header('Expires: 0');
header('Cache-Control: must-revalidate');
header('Pragma: public');
header('Content-Length: ' . filesize($file));
readfile($file);

but upon having the download file, it came out corrupted.i also change the header('Content-Type: application/octet-stream'); to header('Content-Type: application/epub+zip'); but still it was corrupted, i was wondering what is the problem that the file is being corrupted