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