Call sendBeacon for xhr beacons as well
Call sendBeacon for xhr beacons as well

And only subscribe to events once

FredXue/boomerang,lognormal/boomerang,levexis/boomerang,levexis/boomerang,lognormal/boomerang,FredXue/boomerang,sdgdsffdsfff/boomerang,sdgdsffdsfff/boomerang