Upload.cs

public void Upload(string fileToUpload, string host, string username, string password)
{
    try
    {
        using (var sftpClient = new SftpClient(host, username, password))
        using (var fs = new FileStream(fileToUpload, FileMode.Open))
        {
            sftpClient.Connect();

            sftpClient.UploadFile(
                fs,
                "/ftproot/" + Path.GetFileName(fileToUpload),
                uploaded =>
                     {
                         Console.WriteLine($"Uploaded {(double)uploaded / fs.Length * 100}% of the file.");
                     });

            sftpClient.Disconnect();
        }
    }
    catch (Exception e)
    {
        Console.WriteLine(e.Message);
    }
}