/**
  * @param Event $event
  */
 public function pushResponse(Event $event)
 {
     if ($event instanceof StreamReadEvent) {
         $this->pushTrace($event->getRead(), $event->getTime(), self::TRACE_READ);
         return;
     }
     if ($event instanceof StreamWriteEvent) {
         $this->pushTrace($event->getWrite(), $event->getTime(), self::TRACE_WRITE);
         return;
     }
     throw new InvalidArgumentException(sprintf('Invalid Event: "%s"', get_class($event)));
 }