C# HttpClient slow uploading speed

Question

I'm trying to upload large (50 MB - 32 GB) files to Google.Drive. I'm using google-api-dotnet which provides upload logic and encryption support. The main problem is slow uploading speed.

I looked through api source code. Each file is uploaded by chunks (I set chunk size to 4 MB) Each chunk is uploaded via new HttpRequestMessage instance. HttpClient is created once the api service started and reused for all requests.

The upload speed is 600 kbytes/s and stable while my uplink is 10 times faster.

I captured traffic with Wireshark: Each chunk is divided into hundreds or thousands small TLS packets. And for each small TLS packed a confirmation is expected. So the resulting speed is very low.

But when I start Fiddler proxy, the speed becomes as fast as my uplink can do. The TLS packets going very fast in parallel and the confirmations are received later:

I tried my code on 5 PC's with Win7 and all showed similar low uploading speed. But when I tried on Win10 PC - the speed was very good. Also I tried Google.Drive client application and it had same problems with speed. I tried to search about this behaviour, but I didn't found anything.

1. Why are 4 MB chunks divided into 4 KB TLS packets? Can I increase TLS packets size?
2. How can I make the TLS packets sending in parallel as Fiddler does?
3. Or is there other methods of increasing upload speed?

Answer 1

It is highly possible that the problem is the google link, not anything else. I have been uploaded things to google drive with chrome and besides my upload link is giant (50mbps up), google seems limited.