title: Where is the RestRequest class?
body: <p>In the C# tab of <a href="http://documentation.mailgun.net/quickstart.html#sending-messages" rel="noreferrer">the getting started of maingun API</a>, I find the following code.</p>
  
  <pre><code>public static RestResponse SendSimpleMessage() {
         RestClient client = new RestClient();
         client.BaseUrl = "https://api.mailgun.net/v2";
         client.Authenticator =
                 new HttpBasicAuthenticator("api",
                                            "key-3ax6xnjp29jd6fds4gc373sgvjxteol0");
         RestRequest request = new RestRequest();
         request.AddParameter("domain",
                              "samples.mailgun.org", ParameterType.UrlSegment);
         request.Resource = "{domain}/messages";
         request.AddParameter("from", "Excited User &lt;me@samples.mailgun.org&gt;");
         request.AddParameter("to", "sergeyo@profista.com");
         request.AddParameter("to", "serobnic@mail.ru");
         request.AddParameter("subject", "Hello");
         request.AddParameter("text", "Testing some Mailgun awesomness!");
         request.Method = Method.POST;
         return client.Execute(request);
  }
  </code></pre>
  
  <p>When I google the name of the class, I find several reference to this class in different contexts. However, I can't seem to find the fully qualified name of the RestRequest  class anywhere on the mailgun website, google or MSDN to find it's documentation. </p>
  
  <p><strong>Anybody can point out where is this class defined ?</strong></p>