Get values of HttpClient TransportSettings.Credentials in WCF REST 4.0

Question

I have a client wherein I pass in the username, password through network credentials. What I want to do is to pass these two parameters to the service itself for authentication purposes: Example shown below:

Client:

HttpClient client = new HttpClient("http://localhost:8080/ProductService/");
client.TransportSettings.Credentials = 
        new System.Net.NetworkCredential("admin", "admin");

using (HttpResponseMessage response = client.Get("getproducts"))
{
     DataSet dst = new DataSet();
     dst.ReadXml(response.Content.ReadAsStream(), XmlReadMode.ReadSchema);
     return;
}

Service/Server Side:

[OperationContract]
[WebGet(UriTemplate = "getproducts", ResponseFormat = WebMessageFormat.Xml, 
 RequestFormat = WebMessageFormat.Xml, BodyStyle = WebMessageBodyStyle.Wrapped)]
public DataSet GetProducts()
{
     //how can I extract the credentials i passed in the client side?
}

This explains what I want to get done. Hope you all understand what I mean to say.