`header()`를 사용하여 PHP로 파일을 강제로 다운로드하는 방법은 무엇입니까?

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

$quoted = sprintf('"%s"', addcslashes(basename($file), '"\'));
$size = filesize($file);

header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename=' . $quoted);
header('Content-Transfer-Encoding: binary');
header('Connection: Keep-Alive');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header('Content-Length: ' . $size);
readfile($file);