private void Process()
        {
            while (!(_processCancellationTokenSource?.IsCancellationRequested ?? true))
            {
                if (_queue?.Count > 0)
                {
                    do
                    {
                        IQueueItem item = _queue?.Take();
                        item?.Do();

                        if (_processCancellationTokenSource?.IsCancellationRequested ?? true)
                        {
                            break;
                        }
                    } while (_queue?.Count > 0);

                    _queueAddedEvent?.Reset();
                    continue;
                }

                if (_processCancellationTokenSource != null && _queueAddedEvent != null)
                {
                    Debug.WriteLine("Waiting for add next item...");
                    int ret = WaitHandle.WaitAny(new[] { _processCancellationTokenSource.Token.WaitHandle, _queueAddedEvent });
                    if (ret == 0)
                    {
                        break;
                    }

                    if (_queue?.Count == 0)
                    {
                        _queueAddedEvent?.Reset();
                    }
                }
                else
                {
                    break;
                }
                Debug.WriteLine("Queue item arrived");
            }
            Debug.WriteLine("Process task is finished");
        }