public function read($id)
    {
        try {
            $key = $this->datastore->key(
                $this->kind,
                $id,
                ['namespaceId' => $this->namespaceId]
            );
            $entity = $this->transaction->lookup($key);
            if ($entity !== null && isset($entity['data'])) {
                return $entity['data'];
            }
        } catch (Exception $e) {
            trigger_error(
                sprintf('Datastore lookup failed: %s', $e->getMessage()),
                E_USER_WARNING
            );
        }
        return '';
    }