LCUP: updating cookie when no entries are to be sent

I believe LCUP needs to provide a mechanism which
allows the server to send, at any time, a new cookie
to the client without requiring the server to send an
entry.  This is useful in cases where the cookie
the server previously sent is no quite old and
a new cookie would allow more efficient resync
if the session where to be unexpectedly dropped.
In fact, the cookie may be so old to cause a
full sync to occur when no changes would be
necessary if the cookie were updated.

Kurt