docs: public static ImmutableSortedSet<String> hosts(int...ports) {
          if (ports.length == 0) {
              return ImmutableSortedSet.of(
                      HostAndPort.fromParts("", Constants.DEFAULT_INTERNAL_PORT).toString());
          }
          ImmutableSortedSet.Builder<String> sbld = ImmutableSortedSet.naturalOrder();
          for (int p: ports) {
              sbld.add(HostAndPort.fromParts("", p).toString());
          }
          return sbld.build();
      }