title: problems with postasync HttpContent
body: <p>im using PostAsync to call my external webAPI programatically in my back end.</p>
  
  <p>I have had the method working using a httpget, however turning it into a post seems more problematic, due to the httpcontent object required. when awaiting, the status code is always a 404 due to the data not being passed over.</p>
  
  <pre><code> using (var client = new HttpClient())
          {
              client.BaseAddress = new Uri("http://localhost:52715/");
              client.DefaultRequestHeaders.Accept.Clear();
              client.DefaultRequestHeaders.Accept.Add(
                  new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
              var data = JsonConvert.SerializeObject(new { user = "JOHNSMITH" });
              HttpResponseMessage response = await client.PostAsync("MessageUser",  new StringContent(data, Encoding.UTF8, "text/json"));
              if (response.IsSuccessStatusCode)
              {
                  Console.WriteLine("\n sent signal to dept");
              }
          }
  </code></pre>