Bolt\Storage\Field\Type\TemplateFieldsType::set PHP Method

    public function set($entity, $value, $rawData = null)
    {
        $key = $this->mapping['fieldname'];
        $metadata = $this->buildMetadata($entity, $rawData);
        $builder = $this->em->getEntityBuilder('Bolt\\Storage\\Entity\\TemplateFields');
        $builder->setClassMetadata($metadata);
        $templatefieldsEntity = $builder->createFromDatabaseValues($value);
        $ct = new ContentType('templatefields', ['fields' => $metadata->getFieldMappings()]);
        $templatefieldsEntity->setContenttype($ct);
        $entity->{$key} = $templatefieldsEntity;
    }