code: public Observable<NotificationHubResourceInner> createOrUpdateAsync(String resourceGroupName, String namespaceName, String notificationHubName, NotificationHubCreateOrUpdateParameters parameters) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, namespaceName, notificationHubName, parameters).map(new Func1<ServiceResponse<NotificationHubResourceInner>, NotificationHubResourceInner>() {
              @Override
              public NotificationHubResourceInner call(ServiceResponse<NotificationHubResourceInner> response) {
                  return response.body();
              }
          });
      }
docs: Creates/Update a NotificationHub in a namespace.
  
  @param resourceGroupName The name of the resource group.
  @param namespaceName The namespace name.
  @param notificationHubName The notification hub name.
  @param parameters Parameters supplied to the create/update a NotificationHub Resource.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the NotificationHubResourceInner object