public function wrap()
 {
     if ($this->isWrapped) {
         throw new LogicException('The connection has been already wrapped');
     }
     $this->isWrapped = TRUE;
     $this->oldIsolationLevel = parent::getTransactionIsolation();
     parent::setTransactionIsolation(DBALConnection::TRANSACTION_SERIALIZABLE);
     parent::beginTransaction();
 }