CountDownTimer.cs

	public class CountDownTimer
	{
		private Stopwatch _startTimer;
		private TimeSpan _delay;
		private long _currentTick;
		private readonly int _skipTicks;

		private readonly Action<TimeSpan> _tickAction;
		private readonly Action _endAction;

		public CountDownTimer(TimeSpan delay, Action endAction, Action<TimeSpan> tickAction = null, int skipTicks = 20)
		{
			_delay = delay;
			_tickAction = tickAction;
			_skipTicks = skipTicks;
			_endAction = endAction;
		}

		public void Start()
		{
			_startTimer = new Stopwatch();
			_startTimer.Start();
		}

		public void Tick()
		{
			_currentTick++;
			Tick(_currentTick);
		}

		public void Tick(long tickTime)
		{
			_currentTick = tickTime;

			if (_startTimer == null || !_startTimer.IsRunning) return;

			if (_startTimer.IsRunning && tickTime%_skipTicks == 0)
			{
				if (_startTimer.Elapsed > _delay)
				{
					_startTimer.Stop();
					_endAction?.Invoke();
				}
				else
				{
					TimeSpan timeLeft = _delay - _startTimer.Elapsed;
					_tickAction?.Invoke(timeLeft);
				}
			}
		}
	}