Zero length stream return during simultaneous downloads #1740
Description
On one of a servers DownloadFileAsync returns zero length output stream in concurrency scenario without throwing any exceptions.
The server uses virtual folder and some scripts configuration to move files from one folder to another after it was downloaded by client connection.
Files are non zero length. It reproduces ocasionally.
From logs I see this cases: 3 messages downloaded at 21:01:37.457, at 21:01:39 exception after checking for zero length stream written.
3 message downloaded at 2025-11-18 21:25:51.700, at 11/18/2025 21:25:52 exception after checking for zero length stream written.
SSH.NET for both version 2024.2.0, 2025.1.0 .Net 9.