bad.php

<?php

/**
 * Class X_Io_File
 */
class X_Io_File extends Varien_Io_File {

    /**
     * @return void
     */
    public function rewind() {
        rewind($this->_streamHandler);
    }

    /**
     * @return string
     */
    public function getFileName() {
        return $this->_streamFileName;
    }

    /**
     * @param $fileUrl
     */
    static public function batchReturn($fileUrl)
    {
        // This prevents timeouts for bigger files
        $bytesBatch = 1024 * 8;
        @set_time_limit(0);
        $file = @fopen($fileUrl, 'rb');
        while (!feof($file)) {
            echo @fread($file, $bytesBatch);
            ob_flush();
            flush();
        }
    }

}

How not to do streaming file reads if you value not making your PHP processes hotloop forever.