Support navigator.sendBeacon API and handle unload event #30
Description
Currently, BuckyClient has 2 major issues:
- Don't handle unload event, so we might lost tracking data when users click on another link.
- Don't support navigator.sendBeacon API yet. It will support async ajax when users leave the current page (unload event) and also make sure that the tracking data is sent.
If it's ok, I will add a PR.