code: func (s *SeesawSync) Deregister(id SyncSessionID, reply *int) error {
  	s.sync.sessionLock.Lock()
  	session, ok := s.sync.sessions[id]
  	delete(s.sync.sessions, id)
  	s.sync.sessionLock.Unlock()
  
  	if ok {
  		log.Infof("Synchronisation session %d deregistered with %v", id, session.node)
  	}
  
  	return nil
  }
docs: // Deregister deregisters a Seesaw peer for synchronisation.