docs: private void addTransformInterceptors(List<Interceptor<?>> inInterceptors,
                                            List<Interceptor<?>> outInterceptors,
                                            boolean newClient) {
          
          // The old service expects the Customer data be qualified with
          // the 'http://customer/v1' namespace.
          
          // The new service expects the Customer data be qualified with
          // the 'http://customer/v2' namespace.
          
          // If it is an old client talking to the new service then:
          // - the out transformation interceptor is configured for 
          //   'http://customer/v1' qualified data be transformed into
          //   'http://customer/v2' qualified data.
          // - the in transformation interceptor is configured for 
          //   'http://customer/v2' qualified response data be transformed into
          //   'http://customer/v1' qualified data.
         
          // If it is a new client talking to the old service then:
          // - the out transformation interceptor is configured for 
          //   'http://customer/v2' qualified data be transformed into
          //   'http://customer/v1' qualified data.
          // - the in transformation interceptor is configured for 
          //   'http://customer/v1' qualified response data be transformed into
          //   'http://customer/v2' qualified data.
          // - new Customer type also introduces a briefDescription property
          //   which needs to be dropped for the old service validation to succeed
          
          
          // this configuration can be provided externally
          
          Map<String, String> newToOldTransformMap = new HashMap<String, String>();
          newToOldTransformMap.put("{http://customer/v2}*", "{http://customer/v1}*");
          Map<String, String> oldToNewTransformMap = 
              Collections.singletonMap("{http://customer/v1}*", "{http://customer/v2}*");
          
          TransformOutInterceptor outTransform =  new TransformOutInterceptor();
          outTransform.setOutTransformElements(newClient ? newToOldTransformMap 
                                                : oldToNewTransformMap);
          
          if (newClient) {
              newToOldTransformMap.put("{http://customer/v2}briefDescription", "");
              //outTransform.setOutDropElements(
              //    Collections.singletonList("{http://customer/v2}briefDescription"));    
          }
          
          TransformInInterceptor inTransform =  new TransformInInterceptor();
          inTransform.setInTransformElements(newClient ? oldToNewTransformMap 
                                              : newToOldTransformMap);
  
          inInterceptors.add(inTransform);
          outInterceptors.add(outTransform);
          
          
      }