> `bind:duration` is equivalent to `bind:duration={duration}`
Now, when you click on the video, it will update `time`, `duration` and `paused` as appropriate. This means we can use them to build custom controls.
> Ordinarily on the web, you would track `currentTime` by listening for `timeupdate` events. But these events fire too infrequently, resulting in choppy UI. Svelte does better — it checks `currentTime` using `requestAnimationFrame`.