A beacon api for WordPress

[shawfactor]

Forgive me is there is already a ticket for this, I could not find one

Core needs a standard way of sending a beacon as the user leaves a page, with the ability to to hook additional data to the request. Similar to how you can hook data to the heartbeat.

Of course it is possible to build your own solution on this BUT what if some other developer does the same. In the absence of a standard there will be multiple redundant http requests.