code: func (c *Container) add(v uint16) (added bool) {
  
  	if c.isArray() {
  		added = c.arrayAdd(v)
  	} else if c.isRun() {
  		added = c.runAdd(v)
  	} else {
  		added = c.bitmapAdd(v)
  	}
  	if added {
  		c.n++
  	}
  	return added
  }
docs: // add adds a value to the container.