public function recordThat(DomainEvent $event)
    {
        $this->bumpVersion();

        if (is_null($this->uncommittedEvents)) {
            $this->uncommittedEvents = new UncommittedEvents($this->getIdentity());
        }

        $this->uncommittedEvents->append($event);
        $this->when($event);

        return $this;
    }