Support for multiple domains when writing the session cookie

[rwanderc]

Hi Spring Team,

I came up to a situation where I need to issue the session cookie for 2 different domains. Didn't find that in docs neither in code, since org.springframework.boot.web.servlet.server.Session has only 1 Cookie and org.springframework.session.web.http.DefaultCookieSerializer.writeCookieValue() seems to be called only once and also writes to response once.

Is there a way to do it (maybe I'm missing smth)? Or do you plan to have it soon?

For reference, I found these issues that seem to be diff but related #1323 #297 #299 #162 #955