function TThreadedQueue<T>.PopItem(var AQueueSize: Integer; var AItem: T): TWaitResult;
begin
  AItem := Default(T);
  TMonitor.Enter(FQueueLock);
  try
    Result := wrSignaled;
    while (Result = wrSignaled) and (FQueueSize = 0) and not FShutDown do
      if not TMonitor.Wait(FQueueNotEmpty, FQueueLock, FPopTimeout) then
        Result := wrTimeout;

    if (FShutDown and (FQueueSize = 0)) or (Result <> wrSignaled) then
      Exit;

    AItem := FQueue[FQueueOffset];

    FQueue[FQueueOffset] := Default(T);

    Dec(FQueueSize);
    Inc(FQueueOffset);
    Inc(FTotalItemsPopped);

    if FQueueOffset = Length(FQueue) then
      FQueueOffset := 0;

  finally
    AQueueSize := FQueueSize;
    TMonitor.Exit(FQueueLock);
  end;

  TMonitor.Pulse(FQueueNotFull);
end;

if MyQueue.ShutDown then
  if (Res=wrSignaled) and (MyQueue.QueueSize=0) then
    if Value=0 then
       Value is Invalid