title: WebClient Giving 401 unauthorized error when credentials are passed
body: <p>I am trying to access a webapi using <code>WebClient</code>.
  When I set the the property <code>UseDefaultCredentials</code> to true, I am able to access the api. But the headers in the request will have the system login user details which I want to avoid. So I tried creating a network credential  and added the credential to the webclient.
  Then the webclient always gives me 401 unauthorized error. It does not hit the Api. Below is my Code sample:</p>
  
  <pre><code> var webClient = new WebClient()
                  {
                      //UseDefaultCredentials = true,
                      Credentials = new NetworkCredential("username", "password", "domain")
  
                  };
                  var response = webClient.DownloadStringTaskAsync("http://url/api/");
  </code></pre>