title: Unable to set RequestUri of HttpResponseMessage in Web Api Controller
body: <p>I am calling 2 APIs (one orignal and other mock) using HttpClient. </p>
  
  <p>So if the URL of the API call is <code>https://something.com/abc/xyz</code>, when I POST to this url in the response the <code>RequestMessage.RequestUri</code> has a certain value i.e <code>https://something.com/mno/eee?key=asdad</code>.</p>
  
  <p>To replicate this behaviour I have a web api controller setup - </p>
  
  <pre><code>public class JqPay2Controller : ApiController
  {
      [HttpPost]
      [ActionName("donotcare")]
      public HttpResponseMessage DoNotCare()
      {
          var uri = new Uri("https://localhost:3232/mno/eee?key=asdad");
          var contentStr = $"donotcare";
          var res = new HttpResponseMessage(HttpStatusCode.OK)
          {
              Content = new StringContent(contentStr),
              RequestMessage = new HttpRequestMessage(HttpMethod.Post, uri)
          };
          return res;
      }
  }
  </code></pre>
  
  <p>Which my application will call in mock mode and I expect to see the same value in the <code>RequestMessage.RequestUri</code> property.</p>
  
  <p>But I do not see it, instead I see <code>https://something.com/abc/xyz</code> when I expect to see <code>https://localhost:3232/mno/eee?key=asdad</code>.</p>
  
  <p>I am not sure how this works? What am I doing wrong here?</p>