Hostsfile contains known host entries.
New return new hostfile, it will be hosts file also
LookupStaticAddr looks up the hosts for the given address from the hosts file.
LookupStaticHostV4 looks up the IPv4 addresses for the given host from the hosts file.
LookupStaticHostV6 looks up the IPv6 addresses for the given host from the hosts file.
Name return middleware name
ServeDNS implements the Handle interface.