private function rollback()
    {
        // We only need to rollback if we are in a transaction. Otherwise the resulting
        // error would hide the real problem why rollback was called. We might not be
        // in a transaction when not using the transactional locking behavior or when
        // two callbacks (e.g. destroy and write) are invoked that both fail.
        if ($this->inTransaction) {
            if ('sqlite' === $this->driver) {
                $this->pdo->exec('ROLLBACK');
            } else {
                $this->pdo->rollBack();
            }
            $this->inTransaction = false;
        }
    }