[Feature request] Uint8Array values

[kasrak]

Hello! Thanks for this excellent library.

In our app we use Y.js (https://github.com/yjs/yjs) heavily for data models. Currently these get persisted as base64-encoded strings, but there's some overhead in converting the underlying Uint8Array to/from base64.

It would be awesome if we could store Uint8Array directly without converting to base64 (IndexDB on web supports this already).