Upserting vectors with no results

I upsert 15 vectors and the API goes fine w/o exceptions.
Then, right after that I do:

                Pinecone.IndexStats idxStats = await mIndex.DescribeStats(); // my wrapper

and when I look into idxStats.TotalVectorCount - it shows 0.
Does it mean that operation somehow silently failed, or do I need to wait before calling DescribeIndexStats?

Due to async nature of the calls the TotalVectorCount is not immediately available after the call but only after await call completes…