docs: public Observable<ClusterInner> updateAsync(String resourceGroupName, String clusterName, ClusterUpdateParameters parameters) {
          return updateWithServiceResponseAsync(resourceGroupName, clusterName, parameters).map(new Func1<ServiceResponse<ClusterInner>, ClusterInner>() {
              @Override
              public ClusterInner call(ServiceResponse<ClusterInner> response) {
                  return response.body();
              }
          });
      }