what is the use of WebHeaderCollection while downloading a web site,explanation

Hi

here my code to get all headers when your page is downloading,

private void GetHeader()
    {
        Uri uri = new Uri(txtUrl.Text.Trim());
        WebClient myClient = new WebClient();
        // Open the page and get the response as a stream
        Stream response = myClient.OpenRead("http://www.google.com");       
        WebHeaderCollection headers = myClient.ResponseHeaders;
       
        Response.Write("Response headers:
");
        for (int i = 0; i < headers.Count; i++)
        {
            Response.Write(headers.GetKey(i) + " : " + headers.Get(i) + "
");
        }
        StreamReader sr = new StreamReader(response);
        // read the response into a string and show the result.
        string s = sr.ReadToEnd();
        Response.Write(s);
        sr.Close();
        response.Close();
    }

thank you