初学者，有个问题请教

看 batch ping 这个库有个写法不理解,代码如下：

//NewBatchPinger returns a new Pinger struct pointer, interval is default 1s, count default 5

func NewBatchPinger(addrs []string, privileged bool) (batachPinger *BatchPinger, err error) {

	var network string
	if privileged {
		network = "ip"
	} else {
		network = "udp"
	}

	batachPinger = &BatchPinger{
		interval:    time.Second,
		timeout:     time.Second * 100000,
		count:       5,
		network:     network,
		id:          getPId(),
		done:        make(chan bool),
		addrs:       addrs,
		mapIpPinger: make(map[string]*Pinger),
		mapIpAddr:   make(map[string]string),
	}

	return batachPinger, nil
}

函数里的这个 batachPinger 变量没有定义，为啥可以直接用'='，我自己参考写就报错