src/vs/workbench/contrib/notebook/browser/view/renderers/cellRenderer.ts/TimerRenderer/start
class TimerRenderer:	start(startTime: number, adjustment: number): IDisposable {
		this.stop();
		DOM.show(this.container);
		const intervalTimer = setInterval(() => {
			const duration = Date.now() - startTime + adjustment;
			this.container.textContent = this.formatDuration(duration);
		}, 100);
		this.intervalTimer = intervalTimer as unknown as number | undefined;

		return toDisposable(() => {
			clearInterval(intervalTimer);
		});
	}