code: func (cs *clientStore) getSubs(ID string) []*subState {
  	cs.RLock()
  	defer cs.RUnlock()
  	c := cs.clients[ID]
  	if c == nil {
  		return nil
  	}
  	c.RLock()
  	subs := c.getSubsCopy()
  	c.RUnlock()
  	return subs
  }
docs: // GetSubs returns the list of subscriptions for the client identified by ID,
  // or nil if such client is not found.