Delphi 延迟函数

Sleep会引起程序停滞，使程序看起来像死机
下面的延迟方法不会卡主线程

procedure Delay(msecs: DWORD);
var
  iStart, iStop: DWORD;
begin
  iStart := GetTickCount;
  repeat
    iStop := GetTickCount;
    Application.ProcessMessages;
  until (iStop - iStart) >= msecs;
end;