Performance issue to upload a file.

When I want to upload a file, I can either use the method SftpClient.UploadFile or I can use

            using (Stream destinationStream = sftpClient.OpenWrite(destinationPath))
            {
                byte[] buffer = new byte[10 * 1024 * 1024];  // 10 MB buffer
                long totalBytesCopied = 0;
                int currentBlockSize = 0;

                Progress(totalBytesCopied);

                while ((currentBlockSize = fileStream.Read(buffer, 0, buffer.Length)) > 0)
                {
                    destinationStream.Write(buffer, 0, currentBlockSize);

                    totalBytesCopied += currentBlockSize;
                    Progress(totalBytesCopied);
                }
            }

With SftpClient.UploadFile, there is no problem.
But, if I use the previous code, the performances are very, very, very... very... bad.
And I am sure "fileStream.Read" is not the problem.
The method "Progress" is just a Console.WriteLine.

It seems the SftpFileStream is problematic when we want to upload a file.

Can you please fix this problem ?
Thank you very much.

Start by comparing SftpClient.UploadFile with SftpClient.OpenWrite and the SftpFileStream path shown in the issue. Reproduce the upload using the provided loop and measure it against UploadFile; done means the OpenWrite-based upload no longer has the reported severe performance gap.