message: Ensure the CUDA radix sort backend synchronizes before returning; otherwise,
  copies from temporary storage will race with destruction of said temporary
  storage.
  NVC++ FS
diff: @@ -1598,6 +1598,10 @@ namespace __smart_sort {
  {
  cuda_cub::copy(policy, keys.begin(), keys.end(), keys_first);
  }
  +
  + cuda_cub::throw_on_error(
  + cuda_cub::synchronize(policy),
  + "merge_sort: failed to synchronize");
  }
  } // namespace __smart_sort
  