C#, RestSharp, Type or Namespace name "HttpBasicAuthenticator" could not be found

    using System;    using System.Collections.Generic;    using System.Linq;    using System.Text;    using System.Threading.Tasks;    using System.Net.Http;    using System.Net.Http.Headers;    using RestSharp;    namespace ConsoleProgram    {        public class TryingOutRest {            public resttest Execute<resttest>(RestRequest request) where resttest : new() {            var client = new RestClient();                client.BaseUrl = new Uri("http://www.ocrwebservice.com");                client.Authenticator = new HttpBasicAuthenticator("apid", "apikey");// the key and and id are put in as a string, but i removed them for the purposes of this.            var re_quest = new RestRequest();            re_quest.Resource = "/restservices/processDocument";            var response = client.Execute<resttest>(request);            }    }    }

So, hi, trying to get to grips with Rest api, Currently doing a project involving it and OCR, as you can probably tell. Tried this, i thought it would work fine, but I seem to have messed up dearly or some naming has changed and i cant find anything relevant in the autofill menu.Anyone got any idea what's happening?P.s. if questions about install, i used NuGet for that, so i assume there'd be no problem.