code: public Observable<Page<VirtualHubInner>> listByResourceGroupAsync(final String resourceGroupName) {
          return listByResourceGroupWithServiceResponseAsync(resourceGroupName)
              .map(new Func1<ServiceResponse<Page<VirtualHubInner>>, Page<VirtualHubInner>>() {
                  @Override
                  public Page<VirtualHubInner> call(ServiceResponse<Page<VirtualHubInner>> response) {
                      return response.body();
                  }
              });
      }
docs: Lists all the VirtualHubs in a resource group.
  
  @param resourceGroupName The resource group name of the VirtualHub.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;VirtualHubInner&gt; object