public static Pair<String, String> labelKeyValuePair(String indexedLabelKey) {
        var idx = indexedLabelKey.indexOf('=');
        if (idx != -1) {
            return Pair.of(indexedLabelKey.substring(0, idx), indexedLabelKey.substring(idx + 1));
        }
        throw new IllegalArgumentException("Invalid label key-value pair: " + indexedLabelKey);
    }
@Test
    void labelKeyValuePair() {
        var pair = LabelIndexSpecUtils.labelKeyValuePair("key=value");
        assertThat(pair.getFirst()).isEqualTo("key");
        assertThat(pair.getSecond()).isEqualTo("value");

        pair = LabelIndexSpecUtils.labelKeyValuePair("key=value=1");
        assertThat(pair.getFirst()).isEqualTo("key");
        assertThat(pair.getSecond()).isEqualTo("value=1");

        assertThatThrownBy(() -> LabelIndexSpecUtils.labelKeyValuePair("key"))
            .isInstanceOf(IllegalArgumentException.class)
            .hasMessage("Invalid label key-value pair: key");
    }