anchor.diff:  -spec send_notify(inet:ip_address(), inet:ip_address(), binary(), dns:class()) -> ok.
   send_notify(BindIP, DestinationIP, ZoneName, ZoneClass) ->
       Packet =  #dns_message{id = dns:random_id(),
  -        oc = ?DNS_OPCODE_NOTIFY,
  -        rc = ?DNS_RCODE_NOERROR,
  -        aa = true,
  -        qc = 1,
  -        questions = [#dns_query{name = ZoneName, class = ZoneClass, type = ?DNS_TYPE_SOA}]},
  +                           oc = ?DNS_OPCODE_NOTIFY,
  +                           rc = ?DNS_RCODE_NOERROR,
  +                           aa = true,
  +                           qc = 1,
  +                           questions = [#dns_query{name = ZoneName, class = ZoneClass,
  +                                                   type = ?DNS_TYPE_SOA}]},
       {ok, _Recv} = case erldns_encoder:encode_message(Packet) of
  -                     {false, EncodedMessage} ->
  -                         send_tcp_message(BindIP, DestinationIP, EncodedMessage);
  -                     {true, EncodedMessage, Message} when is_record(Message, dns_message) ->
  -                         send_tcp_message(BindIP, DestinationIP, EncodedMessage);
  -                     {false, EncodedMessage, _TsigMac} ->
  -                         send_tcp_message(BindIP, DestinationIP, EncodedMessage);
  -                     {true, EncodedMessage, _TsigMac, _Message} ->
  -                         send_tcp_message(BindIP, DestinationIP, EncodedMessage)
  -                 end,
  +                      {false, EncodedMessage} ->
  +                          send_tcp_message(BindIP, DestinationIP, EncodedMessage);
  +                      {true, EncodedMessage, Message} when is_record(Message, dns_message) ->
  +                          send_tcp_message(BindIP, DestinationIP, EncodedMessage);
  +                      {false, EncodedMessage, _TsigMac} ->
  +                          send_tcp_message(BindIP, DestinationIP, EncodedMessage);
  +                      {true, EncodedMessage, _TsigMac, _Message} ->
  +                          send_tcp_message(BindIP, DestinationIP, EncodedMessage)
  +                  end,
       exit(normal).
   
   handle_notify(Message, ClientIP, ServerIP) ->
  
positive.code:     Acc;
  query_server_for_answers(DestinationIP, BindIP, [Question | Tail], Acc) ->
      Packet = #dns_message{id = dns:random_id(),
          qr = false,
          oc = ?DNS_OPCODE_QUERY,
          aa = false,
          tc = false,
          rd = true,
          ra = false,
          ad = true,
          cd = false,
          rc = ?DNS_RCODE_NOERROR,
          qc = 1,
          adc = 1,
          questions = [Question],
          additional = [#dns_optrr{udp_payload_size = 4096, ext_rcode = ?DNS_ERCODE_NOERROR,
              version = 0, dnssec = false, data = []}]},
      {ok, Recv} = case erldns_encoder:encode_message(Packet) of
                       {false, EncodedMessage} ->
                           send_tcp_message(BindIP, DestinationIP, EncodedMessage);
  
negative.code:     end,
      %% Request SOA from master
      Request = #dns_message{id = dns:random_id(),
                             oc = ?DNS_OPCODE_QUERY,
                             rd = true,
                             qc = 1,
                             questions = [#dns_query{name = ZoneName, class = ?DNS_CLASS_ANY,
                                                     type = ?DNS_TYPE_SOA}]},
      {ok, Recv} = case erldns_encoder:encode_message(Request) of
                       {false, EncodedMessage} ->
                           send_tcp_message(ServerIP, ClientIP, EncodedMessage);
  