hostname{string}
Uses the DNS protocol to resolve a start of authority record (SOA record) for
the hostname. On success, the Promise is resolved with an object with the
following properties:
nsnamehostmasterserialrefreshretryexpireminttl
{nsname: 'ns.example.com',hostmaster: 'root.example.com',serial: 2013101809,refresh: 10000,retry: 2400,expire: 604800,minttl: 3600}
