docs: public void initialize() throws SQLException {
      synchronized (lock) {
        source = createConnectionPool();
        try {
          source.initializeFrom(this);
        } catch (Exception e) {
          throw new PSQLException(GT.tr("Failed to setup DataSource."), PSQLState.UNEXPECTED_ERROR,
              e);
        }
  
        while (available.size() < initialConnections) {
          available.push(source.getPooledConnection());
        }
  
        initialized = true;
      }
    }