จะปิด WCF Netnamedpipebinding Channel ได้อย่างไร?

        Private Sub CloseChannel(ByVal channel As ICommunicationObject)
        Try
            If channel.State = CommunicationState.Opened Then
                Dim caller As New AsyncCallback(AddressOf callback)
                channel.BeginClose(caller, New Object)
                ' channel.Close()
            End If
        Catch ex As Exception
            Log(LogTypes.AllExceptions, "CloseChannel - Error closing the channel. ", ex.ToString)
        Finally
            channel.Abort()
        End Try
    End Sub
using (ServiceReference1.ServiceClient client=new ServiceClient())
            {
                var result = client.Test();
                Console.WriteLine(result);
            }