code: public function set($name, $value)
      {
          $queryBuilder = $this->connection->createQueryBuilder();
          $queryBuilder->from($this->table, 'config')
              ->select(['config.name'])
              ->where('config.name = :name')
              ->setParameter(':name', $name);
          $configElement = $queryBuilder->execute()->fetchColumn();
  
          if ($value instanceof DateTimeInterface) {
              $value = $value->format(DATE_W3C);
          }
  
          if (!empty($configElement)) {
              $this->connection->update(
                  $this->table,
                  [
                      'value' => $value,
                  ],
                  [
                      'name' => $name,
                  ]
              );
          } else {
              $this->connection->insert($this->table, [
                  'name' => $name,
                  'value' => $value,
              ]);
          }
      }
docs: {@inheritdoc}