code: public Observable<Page<ClusterInner>> listByResourceGroupAsync(String resourceGroupName) {
          return listByResourceGroupWithServiceResponseAsync(resourceGroupName).map(new Func1<ServiceResponse<List<ClusterInner>>, Page<ClusterInner>>() {
              @Override
              public Page<ClusterInner> call(ServiceResponse<List<ClusterInner>> response) {
                  PageImpl<ClusterInner> page = new PageImpl<>();
                  page.setItems(response.body());
                  return page;
              }
          });
      }
docs: Lists all Kusto clusters within a resource group.
  
  @param resourceGroupName The name of the resource group containing the Kusto cluster.
  @return the observable to the List&lt;ClusterInner&gt; object