public void ReleaseOperation(string operationKey, T operationResult)
        {
            InstanceQM <T> throttler = null;
            var            isSuccess = RedundantTaskThrottler.TryGetValue(operationKey, out throttler);

            if (isSuccess)
            {
                if (throttler != null)
                {
                    throttler.ReleaseInstance(operationResult);
                }
                RedundantTaskThrottler.TryRemove(operationKey, out throttler);
            }
        }