code: public Observable<ClusterConfigurationsInner> listAsync(String resourceGroupName, String clusterName) {
          return listWithServiceResponseAsync(resourceGroupName, clusterName).map(new Func1<ServiceResponse<ClusterConfigurationsInner>, ClusterConfigurationsInner>() {
              @Override
              public ClusterConfigurationsInner call(ServiceResponse<ClusterConfigurationsInner> response) {
                  return response.body();
              }
          });
      }
docs: Gets all configuration information for an HDI cluster.
  
  @param resourceGroupName The name of the resource group.
  @param clusterName The name of the cluster.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the ClusterConfigurationsInner object