Function<? super T, ? extends K> keyFunction,
          Function<? super T, ? extends V> valueFunction) {
    checkNotNull(keyFunction, "keyFunction");
    checkNotNull(valueFunction, "valueFunction");
    return Collector.of(
        ImmutableListMultimap::<K, V>builder,
        (builder, t) -> builder.put(keyFunction.apply(t), valueFunction.apply(t)),
        ImmutableListMultimap.Builder::combine,

      List<E> list,
      Function<? super E, K> keyFunction,
      K key,
      KeyPresentBehavior presentBehavior,
      KeyAbsentBehavior absentBehavior) {
    checkNotNull(key);
    return binarySearch(
        list, keyFunction, key, Ordering.natural(), presentBehavior, absentBehavior);
  }

  /**

   * stream.collect(ImmutableMap.toImmutableMap(keyFunction, v -> v))}. {@code
   * ImmutableMap.copyOf(stream.collect(Collectors.toMap(keyFunction, v -> v)))}, but be aware that
   * this may not preserve the order of entries.
   *
   * @param keyFunction the function used to produce the key for each value
   * @return a map mapping the result of evaluating the function {@code keyFunction} on each value

      List<E> list,
      Function<? super E, K> keyFunction,
      K key,
      KeyPresentBehavior presentBehavior,
      KeyAbsentBehavior absentBehavior) {
    checkNotNull(key);
    return binarySearch(
        list, keyFunction, key, Ordering.natural(), presentBehavior, absentBehavior);
  }

  /**

   *
   * @param values the values to use when constructing the {@code Map}
   * @param keyFunction the function used to produce the key for each value
   * @return a map mapping the result of evaluating the function {@code keyFunction} on each value
   *     in the input collection to that value
   * @throws IllegalArgumentException if {@code keyFunction} produces the same key for more than one
   *     value in the input collection

   *
   * @param values the values to use when constructing the {@code Map}
   * @param keyFunction the function used to produce the key for each value
   * @return a map mapping the result of evaluating the function {@code keyFunction} on each value
   *     in the input collection to that value
   * @throws IllegalArgumentException if {@code keyFunction} produces the same key for more than one
   *     value in the input collection

  public static <T extends @Nullable Object, K, V>
      Collector<T, ?, ImmutableBiMap<K, V>> toImmutableBiMap(
          Function<? super T, ? extends K> keyFunction,
          Function<? super T, ? extends V> valueFunction) {
    return CollectCollectors.toImmutableBiMap(keyFunction, valueFunction);
  }

  /**
   * Returns the empty bimap.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */

      Collector<T, ?, ImmutableSortedMap<K, V>> toImmutableSortedMap(
          Comparator<? super K> comparator,
          Function<? super T, ? extends K> keyFunction,
          Function<? super T, ? extends V> valueFunction) {
    return CollectCollectors.toImmutableSortedMap(comparator, keyFunction, valueFunction);
  }

  /**
   * Returns a {@link Collector} that accumulates elements into an {@code ImmutableSortedMap} whose

      Collector<T, ?, ImmutableListMultimap<K, V>> toImmutableListMultimap(
          Function<? super T, ? extends K> keyFunction,
          Function<? super T, ? extends V> valueFunction) {
    return CollectCollectors.toImmutableListMultimap(keyFunction, valueFunction);
  }

  /**
   * Returns a {@code Collector} accumulating entries into an {@code ImmutableListMultimap}. Each

   * @param keyFunction the function used to produce the key for each value
   * @return {@code ImmutableListMultimap} mapping the result of evaluating the function {@code
   *     keyFunction} on each value in the input collection to that value
   * @throws NullPointerException if any element of {@code values} is {@code null}, or if {@code
   *     keyFunction} produces {@code null} for any key
   */