protected function _format($type, $message)
{
$key = 'X-Wf-1-1-1-' . $this->_counter++;
$content = array(array('Type' => $this->_levels[$type]), $message);
$content = json_encode($content);
$content = strlen($content) . '|' . $content . '|';
return compact('key', 'content');
}