### Question:
Labels extends ImmutableKeyValuePairs<String, String> { public abstract void forEach(LabelConsumer consumer);  abstract void forEach(LabelConsumer consumer); static Labels empty(); static Labels of(String key, String value); static Labels of(String key1, String value1, String key2, String value2); static Labels of(
      String key1, String value1, String key2, String value2, String key3, String value3); static Labels of(
      String key1,
      String value1,
      String key2,
      String value2,
      String key3,
      String value3,
      String key4,
      String value4); static Labels of(
      String key1,
      String value1,
      String key2,
      String value2,
      String key3,
      String value3,
      String key4,
      String value4,
      String key5,
      String value5); static Labels of(String[] keyValueLabelPairs); Builder toBuilder(); static Builder newBuilder();  }### Answer:
@Test void forEach() { final Map<String, String> entriesSeen = new HashMap<>(); Labels labels = Labels.of( "key1", "value1", "key2", "value2"); labels.forEach(entriesSeen::put); assertThat(entriesSeen).containsExactly(entry("key1", "value1"), entry("key2", "value2")); }