A generic function that I use to work with the Arin Web Service (Whois-RWS). I have created classes out of the resulting xml and included them in the project. That is ultimately what <T> becomes. See section 4.5 (https://www.arin.net/resources/whoisrws/whois_api.html#whoisrws) ARIN's RESTful Resources, for the various resources available.

ArinPortableAPI.cs

namespace ArinPortableAPI
{
    using System;
    using System.IO;
    using System.Net.Http;
    using System.Threading.Tasks;
    using System.Xml.Serialization;
    public class ArinLookup
    {
        public static string ApiUrl = "http://whois.arin.net/rest";
        public async Task<T>GetResource<T>(string restUrl) where T : class
        {
            Stream responseStream = null;
            HttpClient client = new HttpClient();
            try
            {
                responseStream = await client.GetStreamAsync(restUrl);
            }
            catch (Exception ex)
            {
                throw ex;
            }
            XmlSerializer xSerializer = new XmlSerializer(typeof(T));
            T arinReturn = xSerializer.Deserialize(responseStream) as T;
            return arinReturn;
        }
    }
}