docs: public Observable<SubscriptionUsageInner> getAsync(String locationName, String usageName) {
          return getWithServiceResponseAsync(locationName, usageName).map(new Func1<ServiceResponse<SubscriptionUsageInner>, SubscriptionUsageInner>() {
              @Override
              public SubscriptionUsageInner call(ServiceResponse<SubscriptionUsageInner> response) {
                  return response.body();
              }
          });
      }