fetchStreams example

$query = $this->createQuery();

        $this->connection->transactional(function D) use ($query) {
            $this->connection->executeUpdate('DELETE FROM s_customer_search_index');

            while ($ids = $query->fetch()) {
                $this->searchIndexer->populate($ids);
            }
        });

        $streams = $this->fetchStreams();

        if (empty($streams)) {
            return true;
        }

        foreach ($streams as $stream) {
            if ($stream['freeze_up']) {
                $stream['freeze_up'] = new DateTime($stream['freeze_up']);
            } else {
                $stream['freeze_up'] = null;
            }