docs: private static Map<String, List<String>> getZoneBasedDiscoveryUrlsFromRegion(
              DiscoveryClientConfiguration discoveryClientConfiguration,
              String region) {
          String discoveryDnsName = null;
          try {
              discoveryDnsName = "txt." + region + "." + discoveryClientConfiguration.getHost();
  
              LOG.debug("The region url to be looked up is {} :", discoveryDnsName);
              Set<String> zoneCnamesForRegion = new TreeSet<>(DnsResolver.getCNamesFromTxtRecord(discoveryDnsName));
              Map<String, List<String>> zoneCnameMapForRegion = new TreeMap<>();
              for (String zoneCname : zoneCnamesForRegion) {
                  String zone;
                  if (isEC2Url(zoneCname)) {
                      throw new RuntimeException(
                              "Cannot find the right DNS entry for "
                                      + discoveryDnsName
                                      + ". "
                                      + "Expected mapping of the format <aws_zone>.<domain_name>");
                  } else {
                      String[] cnameTokens = zoneCname.split("\\.");
                      zone = cnameTokens[0];
                      LOG.debug("The zoneName mapped to region {} is {}", region, zone);
                  }
                  List<String> zoneCnamesSet = zoneCnameMapForRegion.computeIfAbsent(zone, k -> new ArrayList<>());
                  zoneCnamesSet.add(zoneCname);
              }
              return zoneCnameMapForRegion;
          } catch (Throwable e) {
              throw new RuntimeException("Cannot get cnames bound to the region:" + discoveryDnsName, e);
          }
      }