public static String clientTagPrefix(final String clientTagKey) {
        return CLIENT_TAG_PREFIX + clientTagKey;
    }
@Test
    public void shouldThrowExceptionWhenClientTagsExceedTheLimit() {
        final int limit = StreamsConfig.MAX_RACK_AWARE_ASSIGNMENT_TAG_LIST_SIZE + 1;
        for (int i = 0; i < limit; i++) {
            props.put(StreamsConfig.clientTagPrefix("k" + i), "v" + i);
        }
        final ConfigException exception = assertThrows(ConfigException.class, () -> new StreamsConfig(props));
        assertEquals(
            String.format("At most %s client tags can be specified using %s prefix.",
                          StreamsConfig.MAX_RACK_AWARE_ASSIGNMENT_TAG_LIST_SIZE,
                          StreamsConfig.CLIENT_TAG_PREFIX
            ), exception.getMessage()
        );
    }