docs: private void handleClusterEvent(ClusterMembershipEvent event) {
      threadContext.execute(() -> {
        if (event.type() == ClusterMembershipEvent.Type.MEMBER_REMOVED) {
          for (Session session : sessions.values()) {
            if (session.memberId().equals(event.subject().id())) {
              role.expire((PrimaryBackupSession) session);
            }
          }
        }
      });
    }