Beacon and set cookie

Currently we don't specify how the response to a beacon response will be
handled. Does the browser:
a) close connection right after transmitting the data, or
b) read the response from the server but ignore it, or
c) read the response header to determine whether to follow a redirect or
retry on a server busy error, or
d) do (c) and allow the response to set the cookie on the beacon's url
domain, but ignore response body.

Here's some writeup on <a ping> attribute which is similar to Beacon:
http://www.whatwg.org/specs/web-apps/current-work/multipage/links.html#4.8.4.1

They suggest (d).

If (d) is true, will the set cookie be treated as first or third party
based on whether the url of the document that issued the beacon and the
beacon url are same or different, respectively?


And second question: do we need to specify that the Referer header will be
set to the document's uri or is that implicit?

Arvind