Return the 235 response code if valid, otherwise return the error.
[Visual Basic] Public Function Negotiate( _ ByVal smtpProxy As ISmtpProxy, _ ByVal supportedAuthTypes As String() _ ) _ Implements ISmtpAuthToken.Negotiate As SmtpResponse [C#] public SmtpResponse Negotiate( ISmtpProxy smtpProxy, string[] supportedAuthTypes ); [C++] public: SmtpResponse* Negotiate( ISmtpProxy* smtpProxy, String* supportedAuthTypes __gc[] ); [JScript] public function Negotiate( ISmtpProxy smtpProxy, String[] supportedAuthTypes ): SmtpResponse;