title: How to get LastModified date of the HttpWebResponse in c#?
body: <p>I am trying to create a cache of images for windows phone 8.1. To do this I need to read the property LastModified of HttpWebRequest. I searched google and I found <a href="http://msdn.microsoft.com/es-es/library/system.net.httpwebresponse.lastmodified(v=vs.110).aspx" rel="nofollow">this</a>, does not work. I have this code:</p>
  
  <pre><code>        HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(imageFileUri);
          webRequest.Method="HEAD";
          HttpWebResponse webResponse =  ((HttpWebResponse)await webRequest.GetResponseAsync());
  </code></pre>
  
  <p>What I have to do to get the date?</p>