Waiting and loading spinner is not triggered on fast quality change

[pclarke-coursera]

Whenever the video quality changes for HLS (either manually or via auto resolution switching), there is no loading spinner shown even though the waiting event is triggered. In video.js's source code, we can see that the vjs-waiting class is added which will trigger the loading spinner. However, even though the video player is in a waiting state when you try to switch resolutions quickly, there is no automatic loading spinner.

Expected result:
When a video quality change occurs and the video is buffering, show the loading spinner to appropriately respond to the waiting event.

Reproduction steps:
Visit https://videojs-http-streaming.netlify.app/?debug=false&autoplay=false&muted=false&fluid=false&minified=false&sync-workers=false&liveui=true&llhls=true&url=https%3A%2F%2Fbitdash-a.akamaihd.net%2Fcontent%2FMI201109210084_1%2Fm3u8s-fmp4%2Ff08e80da-bf1d-4e3d-8899-f0f6155f6efa.m3u8&type=application%2Fx-mpegurl&keysystems=&buffer-water=false&exact-manifest-timings=false&pixel-diff-selector=false&network-info=false&dts-offset=false&override-native=true&use-mms=true&preload=auto&mirror-source=true&forced-subtitles=false and try to quickly change the resolutions. Sometimes you will see the video content freeze without any loading spinner to indicate something is happening.

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