I would prefer having the `attach` event, as the other API we have, and just with `worker` as argument, (not `{worker: worker}`).
That's because ideally, in the future, `show` should just "show" the sidebar, without reload, therefore no `worker` would be involved. So having `worker` now as argument here will be awkward.
If we have `attach` event, users can use them as we have in other API, decoupling the "attach" from the "show", so that we do not break anything.

Not sure if I explained that properly.