docs: public Observable<Page<UpgradeOperationHistoricalStatusInfoInner>> getOSUpgradeHistoryAsync(final String resourceGroupName, final String vmScaleSetName) {
          return getOSUpgradeHistoryWithServiceResponseAsync(resourceGroupName, vmScaleSetName)
              .map(new Func1<ServiceResponse<Page<UpgradeOperationHistoricalStatusInfoInner>>, Page<UpgradeOperationHistoricalStatusInfoInner>>() {
                  @Override
                  public Page<UpgradeOperationHistoricalStatusInfoInner> call(ServiceResponse<Page<UpgradeOperationHistoricalStatusInfoInner>> response) {
                      return response.body();
                  }
              });
      }