code: Future<ExtenderConfiguration> getExtensionConfiguration() {
          return new HAConfFuture<>(invokeSubserviceConfUpdates(),
                  new HAConfFuture.ConfResultSupplier<ConsolidatedResult<ExtenderConfiguration>>() {
                      public ConsolidatedResult<ExtenderConfiguration> get() {
                          return lastConsolidatedConfiguration;
                      }
                  });
      }
docs: Gets the extender's configuration. Invokes configuration updates for all the subclients.
  
  @return {@link Future} which eventually provides subconfigurations consolidation result.