docs: ServiceRegistry getServiceRegistry(final boolean modify, final Step registryActiveStep) {
          if (modify) {
              readOnly = false;
          }
  
          assert isControllingThread();
  
          Stage currentStage = this.currentStage;
          if (modify) {
              if (!isRuntimeChangeAllowed()) {
                  throw ControllerLogger.ROOT_LOGGER.serviceRegistryRuntimeOperationsOnly();
              }
          } else {
              assertNotComplete(currentStage);
          }
          authorize(false, modify ? READ_WRITE_RUNTIME : READ_RUNTIME);
          if (modify) {
              ensureWriteLockForRuntime();
          }
          OperationContextServiceRegistry registry = new OperationContextServiceRegistry(modelController.getServiceRegistry(), registryActiveStep);
          serviceRegistries.add(registry);
          return registry;
      }