System.Net.Mail.SmtpConnection.ConnectAndHandshakeAsyncResult.TlsStreamAuthenticate C# (CSharp) Method

            private bool TlsStreamAuthenticate()
            {
                _connection._networkStream = new TlsStream(_connection._networkStream, _connection._tcpClient.Client, _host, _connection._clientCertificates);
                IAsyncResult result = (_connection._networkStream as TlsStream).BeginAuthenticateAsClient(TlsStreamAuthenticateCallback, this);
                if (result.CompletedSynchronously)
                {
                    (_connection._networkStream as TlsStream).EndAuthenticateAsClient(result);
                    _connection._responseReader = new SmtpReplyReaderFactory(_connection._networkStream);
                    SendEHello();
                    return true;
                }
                return false;
            }