code: @SuppressWarnings("unchecked")
      private boolean isAnySecureTransportAddressAvailable(Map<String, Object> extraConfig) {
          Map<String, List<TransportAddress>> addrMap = (Map<String, List<TransportAddress>>) extraConfig.get(ADDR_KEY);
          if (addrMap != null) {
              Set<String> sslAliases = addrMap.keySet();
              return sslAliases.size() != 1;
          }
          return true;
      }
docs: /*
  On a server, the address map will only contain a "null" entry if there are only unsecured transport addresses.
  A client container will not have an address map, so check for its existence and assume there are secured transport
  addresses when an address map is not found.