System.Net.FileWebRequest.CheckAndMarkAsyncGetResponsePending C# (CSharp) Method

        private void CheckAndMarkAsyncGetResponsePending()
        {
            if (Aborted)
            {
                throw CreateRequestAbortedException();
            }

            lock (this)
            {
                if (_readPending)
                {
                    throw new InvalidOperationException(SR.net_repcall);
                }
                _readPending = true;
            }
        }