code: func (e *Engine) shutdownVservers() {
  	for _, v := range e.vservers {
  		v.stop()
  	}
  	for name, v := range e.vservers {
  		<-v.stopped
  		delete(e.vservers, name)
  	}
  	e.vserverLock.Lock()
  	e.vserverSnapshots = make(map[string]*seesaw.Vserver)
  	e.vserverLock.Unlock()
  }
docs: // shutdownVservers shuts down all running vservers.