static byte[] DefaultMachineId()
 {
     byte[] bestMacAddr = MacAddressUtil.GetBestAvailableMac();
     if (bestMacAddr == null)
     {
         bestMacAddr = new byte[MacAddressUtil.MacAddressLength];
         ThreadLocalRandom.Value.NextBytes(bestMacAddr);
         Logger.Warn(
             "Failed to find a usable hardware address from the network interfaces; using random bytes: {}",
             MacAddressUtil.FormatAddress(bestMacAddr));
     }
     return(bestMacAddr);
 }