c# - Media Url in TwiML request message

Question

I have configured a url to receive TwiML message. I receive following fields

1. Account Sid 2.Body 3.From 4.MessageSid 5.NumMedia

However, I dont receive the following

1. MediaContentType
2. MediaUrl

Though the field NumMedia has value 2, I dont receive MediaUrl.

I use c#.

Following is my class structure which will hold the request message received from Twilio

public class TwilioRequest
    {
        public string MessageSid { get; set; }
        public string AccountSid { get; set; }
        public string From { get; set; }
        public string To { get; set; }
        public string Body { get; set; }
        public int NumMedia { get; set; }
        public List<string> MediaContentType { get; set; }
        public List<string> MediaUrl { get; set; }
}

Kindly guide me.