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 callerIds = twilio.ListOutgoingCallerIds(null, null, null, null);

        foreach (var callerId in callerIds.OutgoingCallerIds)
        {
          Console.WriteLine(callerId.PhoneNumber);
        }
    }