mod_ruby with CGI::Session::MemoryStore?

Is it possible to use CGI::Session::MemoryStore with mod_ruby?

It looks to me as if it's not possible, because of the fact that there
are multiple Apache server processes with separate address spaces.
But then, what is the purpose of MemoryStore?  How can it ever be
used? 

Is CGI::Session always only used with mod_ruby, or at least always
only with Apache?  Or, is the idea that you could use it if you had a
(non-Apache) web server in a simple, single Ruby process?  That's the
only way I can think of that would make sense to use MemoryStore.  But
is that realistic?

Cheers,
 - arb