Acess to value on watch callback when available

[dvlden]

Describe the feature

I find it weird that watch method doesn't actually provide me k:v pair for example. Is there any specific reasoning why watcher strictly returns only event and key and can't be customized further?

Building a browser storage driver is not quite good this way. I'd expect in watcher to receive a key and value on update and only key on delete, for example.

With current implementation, I'd need to get the value from the storage, using the key it provides me with, which seem like overhead?

Additional information

• [x] Would you be willing to help implement this feature?