static void Main(string[] args)
    {
        // Find your Account Sid and Auth Token at twilio.com/user/account
        string AccountSid = "ACXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
        string AuthToken  = "your_auth_token";
        var    twilio     = new TwilioRestClient(AccountSid, AuthToken);

        var options = new DomainOptions();

        options.FriendlyName = "My Domain";
        options.VoiceUrl     = "https://demo.twilio.com/welcome";
        options.AuthType     = "IP_ACL";
        options.DomainName   = "marlo.sip.twilio.com";
        var domain = twilio.CreateDomain(options);

        Console.WriteLine(domain.Sid);
    }