public static void releaseSession(long id) {
   synchronized (sSessions) {
     NgnPublicationSession session = NgnPublicationSession.getSession(id);
     if (session != null) {
       session.decRef();
       sSessions.remove(id);
     }
   }
 }
 public static void releaseSession(NgnPublicationSession session) {
   synchronized (sSessions) {
     if (session != null && sSessions.containsKey(session.getId())) {
       long id = session.getId();
       session.decRef();
       sSessions.remove(id);
     }
   }
 }