Multimap<K, V> synchronizedMultimap(Multimap<K, V> multimap) {
    return Synchronized.multimap(multimap, null);
  }

  /**
   * Returns an unmodifiable view of the specified multimap. Query operations on the returned
   * multimap "read through" to the specified multimap, and attempts to modify the returned
   * multimap, either directly or through the multimap's views, result in an {@code

      Multimap<K, V> synchronizedMultimap(Multimap<K, V> multimap) {
    return Synchronized.multimap(multimap, null);
  }

  /**
   * Returns an unmodifiable view of the specified multimap. Query operations on the returned
   * multimap "read through" to the specified multimap, and attempts to modify the returned
   * multimap, either directly or through the multimap's views, result in an {@code

  }

  static <K extends @Nullable Object, V extends @Nullable Object> Multimap<K, V> multimap(
      Multimap<K, V> multimap, @Nullable Object mutex) {
    if (multimap instanceof SynchronizedMultimap || multimap instanceof BaseImmutableMultimap) {
      return multimap;
    }
    return new SynchronizedMultimap<>(multimap, mutex);
  }

  }

  static <K extends @Nullable Object, V extends @Nullable Object> Multimap<K, V> multimap(
      Multimap<K, V> multimap, @Nullable Object mutex) {
    if (multimap instanceof SynchronizedMultimap || multimap instanceof BaseImmutableMultimap) {
      return multimap;
    }
    return new SynchronizedMultimap<>(multimap, mutex);
  }

    val values: List<String> = headers.values("")
    val byteCount: Long = headers.byteCount()
    val builder: Headers.Builder = headers.newBuilder()
    val multimap: Map<String, List<String>> = headers.toMultimap()
  }

  @Test
  fun headersBuilder() {
    var builder: Headers.Builder = Headers.Builder()
    builder = builder.add("")
    builder = builder.add("", "")

labels.search_result_cache=Cache
labels.search_result_similar=Resultados semelhantes ({0})
labels.facet_label_title=Rótulo
labels.facet_timestamp_title=Período
labels.facet_timestamp_1day=Últimas 24 horas
labels.facet_timestamp_1week=Última semana
labels.facet_timestamp_1month=Último mês
labels.facet_timestamp_1year=Último ano
labels.facet_timestamp_3month=Últimos 3 meses
labels.facet_timestamp_6month=Últimos 6 meses

labels.search_result_sort_content_length_asc=Dimensione (asc)
labels.search_result_sort_content_length_desc=Dimensione (desc)
labels.search_result_sort_last_modified_asc=Ultima modifica (asc)
labels.search_result_sort_last_modified_desc=Ultima modifica (desc)
labels.search_result_sort_click_count_asc=Clic (asc)
labels.search_result_sort_click_count_desc=Clic (desc)
labels.search_result_sort_favorite_count_asc=Preferiti (asc)

				"application/vnd.ms-works",
				"application/vnd.ms-wpl",
				"application/vnd.ms-xpsdocument",
				"application/vnd.mseq",
				"application/vnd.msign",
				"application/vnd.multiad.creator",
				"application/vnd.multiad.creator.cif",
				"application/vnd.music-niff",
				"application/vnd.musician",
				"application/vnd.muvee.style",
				"application/vnd.ncd.control",
				"application/vnd.ncd.reference",

labels.search_result_cache=Caché
labels.search_result_similar=Resultados similares ({0})
labels.facet_label_title=Etiqueta
labels.facet_timestamp_title=Período
labels.facet_timestamp_1day=Últimas 24 horas
labels.facet_timestamp_1week=Última semana
labels.facet_timestamp_1month=Último mes
labels.facet_timestamp_1year=Último año
labels.facet_timestamp_3month=Últimos 3 meses
labels.facet_timestamp_6month=Últimos 6 meses

        assertThrows(
            IllegalArgumentException.class,
            () -> Maps.uniqueIndex(ImmutableSet.of("one", "uno"), Functions.constant(1)));
    assertThat(expected).hasMessageThat().contains("Multimaps.index");
  }

  /** Null values are not allowed. */
  public void testUniqueIndexNullValue() {
    List<@Nullable String> listWithNull = Lists.newArrayList((String) null);
    assertThrows(