iOS不通过PHP的标题播放mp3文件

Question

I use below code for return audio file

$file = "folder/$file.mp3";
if(file_exists($file)){
    $mime = mime_content_type($file);

    header('Cache-Control: no-store, no-cache, must-revalidate, max-age=0');
    header('Cache-Control: post-check=0, pre-check=0', false);
    header('Pragma: no-cache');

    header('Content-type: application/octet-stream');

    header('Content-Disposition: attachment; filename='.basename($file.'');
    header("Content-Transfer-Encoding: Binary");
    header('Content-Length: '.filesize($file));
    header('X-Accel-Redirect: /files/'.$file);
}

This code work on all devices, but on iOS device not work

I use below code and converted to live stream, but I don't use live stream

$fp = fopen($_SERVER["SCRIPT_FILENAME"], "r");
$etag = md5(serialize(fstat($fp))); 
fclose($fp); 
header('Etag: '.$etag); 
readfile($file);