Emit based on link click (for downloads)

Instead of sending the emit based on an invisible field formatter. Is it possible to trigger the emitter based on another event?

What I want to achieve is registering a nodes popularity based on its attached files being downloaded. So ideally I would attach a callback to the file links which then triggers a radioactivity emitter.

I'm intending to write the code myself but could do with some pointers for getting started. On the PHP server side I think I understand what I need to do (e.g. setup the server to accept an event like _radioactivity_register_emitter()) but I don't understand what I should do to send an emitter? I don't fully understand what is going on with the additional methods in Drupal.behaviors.radioactivity such as hardStore() or more importantly, where those methods are called?

Any help would be much appreciated and thanks for the great module.