docs: @SuppressWarnings("SynchronizationOnLocalVariableOrMethodParameter")
      public List<Connection> getConnections(final ConnectionMode connectionMode, final String dataSourceName, final int connectionSize, final TransactionType transactionType) throws SQLException {
          DataSource dataSource = dataSources.get(dataSourceName);
          if (1 == connectionSize) {
              return Collections.singletonList(createConnection(transactionType, dataSourceName, dataSource));
          }
          if (ConnectionMode.CONNECTION_STRICTLY == connectionMode) {
              return createConnections(transactionType, dataSourceName, dataSource, connectionSize);
          }
          synchronized (dataSource) {
              return createConnections(transactionType, dataSourceName, dataSource, connectionSize);
          }
      }