code: func SetConfReloader(cpath string, reloader func(nc, c *Config), confItems ...string) {
  	reloadConfPath = cpath
  	confReloader = reloader
  	for _, item := range confItems {
  		supportedReloadConfigs[item] = struct{}{}
  		supportedReloadConfList = append(supportedReloadConfList, item)
  	}
  }
docs: // SetConfReloader sets reload config path and a reloader.
  // It should be called only once at start time.