File download with rename and speed limit

I have seen some site provide download limit when download a file from the site. From this technique I am inspire to write the function. This function allow download file with rename and download speed limit.

<?php /** * This function allow download a file with speed limit * $local_file = 'test-file.zip'; local file that should be send to the client * $download_file = 'your-download-name.zip'; filename that the user gets as default * $download_rate = 20.5; set the download rate limit (=> 20,5 kb/s) * * @param string $local_file * @param string $download_file * @param float $download_rate */ function downloadFileWithSpeedLimit($local_file, $download_file, $download_rate ){ if(file_exists($local_file) && is_file($local_file)) { // send headers header('Cache-control: private'); header('Content-Type: application/octet-stream'); header('Content-Length: '.filesize($local_file)); header('Content-Disposition: filename='.$download_file); // flush content flush(); // open file stream $file = fopen($local_file, "r"); while (!feof($file)) { // send the current file part to the browser print fread($file, round($download_rate * 1024)); // flush the content to the browser flush(); // sleep one second sleep(1); } // close file stream fclose($file); } else { die('Error: The file '.$local_file.' does not exist!'); } } ?>