CI_Zip::download PHP Method

    public function download($filename = 'backup.zip')
    {
        if (!preg_match('|.+?\\.zip$|', $filename)) {
            $filename .= '.zip';
        }
        get_instance()->load->helper('download');
        $get_zip = $this->get_zip();
        $zip_content =& $get_zip;
        force_download($filename, $zip_content);
    }