docs: public Observable<List<ProtectionContainerResourceInner>> listAsync(String vaultName, String resourceGroupName, String filter) {
          return listWithServiceResponseAsync(vaultName, resourceGroupName, filter).map(new Func1<ServiceResponse<List<ProtectionContainerResourceInner>>, List<ProtectionContainerResourceInner>>() {
              @Override
              public List<ProtectionContainerResourceInner> call(ServiceResponse<List<ProtectionContainerResourceInner>> response) {
                  return response.body();
              }
          });
      }