public override WebResponse GetResponse()
        {
            if (Proxy == null)
            {
                throw new InvalidOperationException("Proxy property cannot be null.");
            }
            if (String.IsNullOrEmpty(Method))
            {
                throw new InvalidOperationException("Method has not been set.");
            }

            if (RequestSubmitted)
            {
                return _response;
            }
            _response = InternalGetResponse();
            RequestSubmitted = true;
            return _response;
        }