Mine

 header('Expires: 0');
 header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
 header( 'Content-disposition: attatchment; filename='.$filename."\n");
 header( 'Content-type: '.$filemime."\n");
 header( 'Content-length: '.filesize($fileloc)."\n\n");
 header("Content-transfer-encoding: binary");
 header("Accept-Ranges: bytes");
 $handle = fopen($fileloc, 'r') or die( "Can't open file.");
 flush();
 $speed=1024;
 while (!feof($handle)) {
 print(fread($handle, $speed));
 set_time_limit(0);
 flush();
 }
 fclose($handle);