Dummy download tester for PHP with data throttling

dummy_download.php

<?php
/**
 * Long file download tester.
 * You can test very long file downloads using PHP.
 */
ob_start(); 

/**
 * Settings
 */

/** @var string $fileName **/
$fileName = 'test.bin';

/** @var integer $fileSize in bytes **/
$fileSize = 1000000 * 1024;

/** @var integer $uploadLimitPublic Limit in kb/s **/
$uploadLimit = 1024;

/** @var integer $currentSize i bytes **/
$currentSize = 0;

// size of one loop
$s = round( $uploadLimit * 1024 );
 
/**
 * Helpers
 */
 
/**
 * Send header fo file downloading
 * @link http://zinoui.com/blog/download-large-files-with-php
 */
function sendHeaders($fileSize, $type, $name)
{

    header('Pragma: public');
    header('Expires: 0');
    header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
    header('Cache-Control: private', false);
    header('Content-Transfer-Encoding: binary');
    header('Content-Disposition: attachment; filename="'.$name.'";');
    header('Content-Type: ' . $type);
    header('Content-Length: ' . $fileSize );
}

/**
 * APP
 */

// send browser headers
sendHeaders( $fileSize, 'application/octet-stream', $fileName  );

while ( $currentSize < $fileSize)  {
 
	// data buffer to return
	$t = str_repeat( 'a', $s);
 
    $currentSize += $s;
                 
    // Send the current part of the file to the browser
    echo $t;
                     
    // Flush the content
    ob_flush();
	flush();
	
    // Sleep one second
	sleep(1);
}