code: @Override
      protected void onIteration(String containerName, CardinalityEstimatorContainer container) {
          CardinalityEstimatorConfig cardinalityEstimatorConfig = config.findCardinalityEstimatorConfig(containerName);
  
          containerNames.put(container, containerName);
          containerPolicies.put(container, cardinalityEstimatorConfig.getMergePolicyConfig());
      }
docs: The {@link CardinalityEstimatorContainer} doesn't know its name or configuration, so we create these lookup maps.
  This is cheaper than storing this information permanently in the container.