func (s *store) Recovery(state []byte) error {
	s.worldLock.Lock()
	defer s.worldLock.Unlock()
	err := json.Unmarshal(state, s)

	if err != nil {
		return err
	}

	s.ttlKeyHeap = newTtlKeyHeap()

	s.Root.recoverAndclean()
	return nil
}
func (s *store) Recovery(state []byte) error {
	s.worldLock.Lock()
	defer s.worldLock.Unlock()
	err := json.Unmarshal(state, s)

	if err != nil {
		return err
	}

	s.ttlKeyHeap = newTtlKeyHeap()

	s.Root.recoverAndclean()
	return nil
}
// Recovery recovers the store system from a static state
// It needs to recover the parent field of the nodes.
// It needs to delete the expired nodes since the saved time and also
// needs to create monitoring go routines.