Using ffmpeg.wasm in a PWA? Load it from the PWA cache?

**Is your feature request related to a problem? Please describe.**
I would like to use ffmpeg.wasm in a PWA.

**Describe the solution you'd like**
I want ffmpeg.wasm to load from the PWA cache.

**Describe alternatives you've considered**
I have no idea yet how to do this.

**Additional context**
The PWA I am writing should be possible to use by people on slow networks. (Videos might be stored locally on device.)