void Start()
{
	var mouseDownStream = Observable.EveryUpdate().Where(_ => Input.GetMouseButtonDown(0));
	var mouseUpStream = Observable.EveryUpdate().Where(_ => Input.GetMouseButtonUp(0));

	var shootStream = mouseDownStream
		// flat the mouseDown with the 0.1s interval
		.SelectMany(_ => Observable.Interval(TimeSpan.FromSeconds(0.1f)))
		.TakeUntil(mouseUpStream)// stop shooting when mouseUp emit
		.RepeatSafe()// repeat the process
		.Subscribe(_ => Shoot());
}

void Shoot()
{}