code: func NetworkOptionEnableIPv6(enableIPv6 bool) NetworkOption {
  	return func(n *network) {
  		if n.generic == nil {
  			n.generic = make(map[string]interface{})
  		}
  		n.enableIPv6 = enableIPv6
  		n.generic[netlabel.EnableIPv6] = enableIPv6
  	}
  }
docs: // NetworkOptionEnableIPv6 returns an option setter to explicitly configure IPv6