FileStream.CopyToAsync copies the file empty with size of 0

Hi

I'm trying to upload files to some destination folder in wwwroot source folder.

Now when I browse some file and save a new record in the view, the file is copied but empty with 0 size!

I've tried to put these bold in the method:

                using (var fileStream = new FileStream(newfilepath, FileMode.Create))
                {
                    fileStream.Position = 0;
                    fileStream.Flush();
                    await fileStream.CopyToAsync(fileStream);
                }

but this doesn't solve the problem. How to solve please?