/// <summary>
        /// Mark the DNSRecord as Offline.
        /// </summary>
        public void SetOffline()
        {
            IPAddress address = IPAddress.Parse("0.0.0.0");

            IPRecord record = new IPRecord
            {
                IP       = address,
                IPStatus = "OFFLINE"
            };

            List <IPRecord> records = new List <IPRecord>
            {
                record
            };

            this.IPRecords = records;
            this.DNSStatus = "OFFLINE";
        }
        /// <summary>
        /// Preform DNS Query to gather IPV4 IP's.
        /// </summary>
        /// <param name="capsule"></param>
        public static void Execute(IKLog klog, ref Capsule capsule)
        {
            try
            {
                // for each DNS Record
                foreach (var article in capsule.DNSRecords)
                {
                    try
                    {
                        var             count                = 0;
                        List <IPRecord> ipRecordQuickList    = new List <IPRecord>();
                        List <IPRecord> ipRecordTransferList = new List <IPRecord>();

                        // DNS query multiple times
                        while (count < 3)
                        {
                            var ips = Dns.GetHostAddresses(article.DNSName);

                            klog.Metric($"ipcount-{article.DNSName}", ips.Length);

                            // DNS query may return more than one ip
                            foreach (var ip in ips)
                            {
                                IPRecord record = new IPRecord();

                                record.IP       = ip;
                                record.IPStatus = "ONLINE";

                                ipRecordQuickList.Add(record);
                            }

                            Thread.Sleep(5);

                            count++;
                        }

                        var ipRecordDistinctList = ipRecordQuickList.GroupBy(ip => ip.IP).Select(y => y.First());

                        foreach (var ipRecord in ipRecordDistinctList)
                        {
                            var hitCount = ipRecordQuickList.Select(x => x.IP == ipRecord.IP).Count();

                            ipRecordTransferList.Add(ipRecord);
                        }

                        article.IPRecords = ipRecordTransferList;
                        article.DNSStatus = "ONLINE";
                    }
                    catch (Exception ex)
                    {
                        if (ex.ToString().Contains("No such host is known"))
                        {
                            klog.Error($"Exception: Unknow Host. {article.DNSName}");
                        }
                        else
                        {
                            klog.Error($"Exception: {ex}");
                        }

                        article.SetOffline();
                    }
                }
            }
            catch (Exception e)
            {
                klog.Error($"GetIPAddress - Exception: {e}");
            }
        }