Add two session attributes for private storage for transport protocols.
Add two session attributes for private storage for transport protocols.

gquintard/Varnish-Cache,varnish/Varnish-Cache,feld/Varnish-Cache,varnish/Varnish-Cache,varnish/Varnish-Cache,feld/Varnish-Cache,varnish/Varnish-Cache,feld/Varnish-Cache,varnish/Varnish-Cache,gquintard/Varnish-Cache,feld/Varnish-Cache,gquintard/Varnish-Cache,feld/Varnish-Cache,gquintard/Varnish-Cache