code: func NewServer(cfg *ServerConfig) *Server {
  	if cfg == nil {
  		defaultCfg := DefaultServerConfig()
  		cfg = &defaultCfg
  	}
  	return &Server{
  		config: cfg,
  
  		healthchecks: make(map[Id]*Check),
  		notify:       make(chan *Notification, cfg.ChannelSize),
  		configs:      make(chan map[Id]*Config),
  		batch:        make([]*Notification, 0, cfg.BatchSize),
  
  		quit: make(chan bool, 1),
  	}
  }
docs: // NewServer returns an initialised healthcheck server.