为什么Go在名称解析中两次查询/ etc / hosts？

Recently I am reading source code of net package of Go. When I was diving into the name resolution part, it looked like Go had queried /etc/hosts twice:

First in net/dnsclient_unix.gogoLookupHostOrder:

func (r *Resolver) goLookupHostOrder(ctx context.Context, name string, order hostLookupOrder) (addrs []string, err error) {
    if order == hostLookupFilesDNS || order == hostLookupFiles {
        // Use entries from /etc/hosts if they match.
        addrs = lookupStaticHost(name)
        if len(addrs) > 0 || order == hostLookupFiles {
            return
        }   
    }   
    ips, _, err := r.goLookupIPCNAMEOrder(ctx, name, order)

Then in goLookupIPCNAMEOrder:

func (r *Resolver) goLookupIPCNAMEOrder(ctx context.Context, name string, order hostLookupOrder) (addrs []IPAddr, cname dnsmessage.Name, err error) {
    if order == hostLookupFilesDNS || order == hostLookupFiles {
        // goLookupIPFiles invokes lookupStaticHost internally.
        addrs = goLookupIPFiles(name)
        if len(addrs) > 0 || order == hostLookupFiles {
            return addrs, dnsmessage.Name{}, nil
        } 
    } 

So is this a bug? Or It does have some reason but not documented?