Currently additional network requests used by Picard modules or plugins to load additional data for an album all have to register this call on the album and make sure to release it again. Only if a plugin handles this correctly the album will be shown as till loading and get finalized once all requests are finished.

However, there is no proper API for this. All plugins currently do something like this:

album._requests += 1

1. do the request

1. in the callback

album._requests -= 1

album._finalize_loading()

We should offer a proper API for this