code: public com.google.api.ads.admanager.axis.v201902.DeliveryForecastSource getDeliveryForecastSource() {
          return deliveryForecastSource;
      }
docs: Gets the deliveryForecastSource value for this LineItemSummary.
  
  @return deliveryForecastSource   * Strategy for choosing forecasted traffic shapes to pace line
  items. This field is optional and
  defaults to {@link DeliveryForecastSource#HISTORICAL}.