Visual progress update is janky

[slightlyoff]

This element is awesome!

One minor thing I noticed in the demo is that the visual progress updates at something less than 60fps, causing the progress bar to feel janky. During normal playback, maybe it makes sense to use a Web Animation or CSS Animation to smoothly animate at a given rate instead of setting the location at each interval? This is also more likely to move that work off the main thread and keep things smooth on low-end devices.

[gorork]

Thanks @slightlyoff! Nice suggestion 👍