def reap_expired_sessions
      @timestamps.each do |session_id,stamp|
        delete_session(session_id) if (stamp + @session_ttl) < Time.now 
      end
      GC.start
    end
def reap_expired_sessions
      @timestamps.each do |session_id,stamp|
        delete_session(session_id) if (stamp + @session_ttl) < Time.now 
      end
      GC.start
    end
Deletes any sessions that have reached their maximum validity.

 :api: private