public object BeforeSendRequest(ref System.ServiceModel.Channels.Message request, System.ServiceModel.IClientChannel channel)
    {
        CustomMessageHeader header = new CustomMessageHeader();

        request.Headers.Add(header);
        return(null);
    }
    public object BeforeSendRequest(ref Message request, IClientChannel channel)
    {
        CustomMessageHeader header = new CustomMessageHeader();

        request.Headers.RemoveAt(0);
        request.Headers.Add(header);
        return(request);
    }