code: func (cs *channelStore) create(s *StanServer, name string, sc *stores.Channel) (*channel, error) {
  	c := &channel{name: name, store: sc, ss: s.createSubStore(), stan: s, nextSubID: 1}
  	lastSequence, err := c.store.Msgs.LastSequence()
  	if err != nil {
  		return nil, err
  	}
  	c.nextSequence = lastSequence + 1
  	cs.channels[name] = c
  	cl := cs.store.GetChannelLimits(name)
  	if cl.MaxInactivity > 0 {
  		c.activity = &channelActivity{maxInactivity: cl.MaxInactivity}
  	}
  	return c, nil
  }
docs: // low-level creation and storage in memory of a *channel
  // Lock is held on entry or not needed.