code: public Observable<NamespaceResourceInner> createOrUpdateAsync(String resourceGroupName, String namespaceName, NamespaceCreateOrUpdateParameters parameters) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, namespaceName, parameters).map(new Func1<ServiceResponse<NamespaceResourceInner>, NamespaceResourceInner>() {
              @Override
              public NamespaceResourceInner call(ServiceResponse<NamespaceResourceInner> response) {
                  return response.body();
              }
          });
      }
docs: Creates/Updates a service namespace. Once created, this namespace's resource manifest is immutable. This operation is idempotent.
  
  @param resourceGroupName The name of the resource group.
  @param namespaceName The namespace name.
  @param parameters Parameters supplied to create a Namespace Resource.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the NamespaceResourceInner object