(PECL event >= 1.2.6-beta)
EventDnsBase::addNameserverIp — Adds a nameserver to the DNS base
$ip
   ): boolAdds a nameserver to the evdns_base.
ip
    
      The nameserver string, either as an IPv4 address, an IPv6 address, an
      IPv4 address with a port (
      IPv4:Port
      ), or an IPv6 address with a port (
      [IPv6]:Port
      ).
     
   成功时返回 true, 或者在失败时返回 false。