title: IdentityUser not serializing Web Api
body: <p>Not sure what is going on here.  </p>
  
  <p>I am exposing the Identity functionality through a Web API project.  The CRUD aspect will be exposed to an admin app and the login, registration in a public facing app.  </p>
  
  <p>Right now I am just trying to return a list of all users in the database through a Web Api controller action.  I am getting nothing output to the response, but I do get back data from the service:  </p>
  
  <pre><code>        /// &lt;summary&gt;
      /// 
      /// &lt;/summary&gt;
      /// &lt;returns&gt;&lt;/returns&gt;
      [HttpGet]
      [Route("")]
      public async Task&lt;IHttpActionResult&gt; GetAllUsers()
      {
          var model = await _userService.GetAllUsers(); //&lt;---Gets List&lt;AppUser&gt; here?
          return Ok(model);
      }
  </code></pre>
  
  <p>This action shows nothing on fiddler or Postman?</p>
  
  <p>Any ideas? </p>
  
  <pre><code>   public class AppUser : IdentityUser
     {
          public DateTime Created { get; set; }
     }
  </code></pre>
  
  <p>Is there something special about the IdentityUser class that prevents it from being serialized?</p>
  
  <p>Here is the web api serialization config:</p>
  
  <pre><code>config.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;
          config.Formatters.Add(new JsonFormatter());
  
  
      }
  
      public class JsonFormatter : JsonMediaTypeFormatter
      {
          public JsonFormatter()
          {
              this.SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/html"));
              this.SerializerSettings.Formatting = Formatting.Indented;
          }
  
          public override void SetDefaultContentHeaders(Type type, HttpContentHeaders headers, MediaTypeHeaderValue mediaType)
          {
              base.SetDefaultContentHeaders(type, headers, mediaType);
              headers.ContentType = new MediaTypeHeaderValue("application/json");
          }
      }
  </code></pre>