public void TestQuote(string host, int port, FtpsSecurityProtocol protocol,
            string user, string pwd, string server)
        {
            using (FtpsClient c = new FtpsClient(host, port, protocol))
            {
                c.AlwaysAcceptServerCertificate = true;
                c.Open(user, pwd);
                Assert.IsTrue(c.IsConnected);
                string result = c.Quote("HELP");

            }
        }