Currently plugins are called when metadata is retrieved to allow for extra tags to be written.
I would find it useful to be able to write plugins that start after the user clicks save.
Starting an action at this stage ensures that the user is happy with the results so the metadata can be considered final at this stage.

The final file name and metadata should be a parameter to the call back

Possible use cases:

• Running a tool over the saved file such as submitting data to acousticbrainz.
• Automatically adding items to a musicbrainz collection of artists, recordings or works etc.