Flarum\Api\Serializer\DiscussionBasicSerializer::startPost PHP Method

protected startPost ( $discussion ) : Relationship
return	Tobscure\JsonApi\Relationship

    protected function startPost($discussion)
    {
        return $this->hasOne($discussion, 'Flarum\\Api\\Serializer\\PostBasicSerializer');
    }

DiscussionBasicSerializer