HMR

To be aligned to community efforts it would be nice if we could match this spec for HMR
https://github.com/snowpackjs/esm-hmr

This might be slightly tied to #9 so We might want to keep it in mind while trying to come with a solution

Start by reading the linked esm-hmr specification and the discussion in issue #9; the issue names no repository files, tests, or entry points. Determine the required compatibility scope and how it relates to #9, then define completion as an agreed implementation that matches the selected parts of the specification.

Written by the indexing model from the issue text.