title: Unable to set range header for HttpWebRequest in windows 8 store application
body: <p>I am unable to set range header for HttpWebRequest in windows 8 store application, if I try to set the range in different ways as in below sample code I encounter the following exception,
  The 'Range' header must be modified using the appropriate property or method.Parameter name: name.</p>
  
  <p>What are my alternatives to set the range header with following conditions.
  1.Immediate response callback  by setting  AllowReadStreamBuffering = false; so that I continuously write it to a file and get download progress.</p>
  
  <p>Code is:</p>
  
  <pre><code>WebHeaderCollection headers = new WebHeaderCollection();
  headers[HttpRequestHeader.Range] = "bytes=" + CurrentBufferPointer + "-"; 
  
  HttpWebRequest DownLoadClient = (HttpWebRequest)WebRequest.Create(this.FileUri);
  DownLoadClient.Method = "GET";
  DownLoadClient.AllowReadStreamBuffering = false;
  </code></pre>
  
  <p>// setting either of two below ways throws an exception</p>
  
  <pre><code>DownLoadClient.Headers = headers;   
  Or 
  DownLoadClient.Headers[HttpRequestHeader.Range] = "bytes=" + CurrentBufferPointer +  "-";
  
  DownLoadClient.BeginGetResponse(new AsyncCallback(GetResponseCallback), DownLoadClient);
  </code></pre>
  
  <p>When I am setting  DownLoadClient.Headers = headers; this exception will come : </p>