code: public Observable<Page<ControllerInner>> listByResourceGroupAsync(final String resourceGroupName) {
          return listByResourceGroupWithServiceResponseAsync(resourceGroupName)
              .map(new Func1<ServiceResponse<Page<ControllerInner>>, Page<ControllerInner>>() {
                  @Override
                  public Page<ControllerInner> call(ServiceResponse<Page<ControllerInner>> response) {
                      return response.body();
                  }
              });
      }
docs: Lists the Azure Dev Spaces Controllers in a resource group.
  Lists all the Azure Dev Spaces Controllers with their properties in the specified resource group and subscription.
  
  @param resourceGroupName Resource group to which the resource belongs.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;ControllerInner&gt; object