*     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableSetMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableSetMultimap.Builder<Character, String>()
   *         .put('b', "anana")
   *         .putAll('a', "pple", "sparagus")

   * are broken arbitrarily.
   *
   * <p>For example:
   *
   * <pre>{@code
   * Stream.of("foo", "quux", "banana", "elephant")
   *     .collect(greatest(2, comparingInt(String::length)))
   * // returns {"elephant", "banana"}
   * }</pre>
   *
   * <p>This {@code Collector} uses O(k) memory and takes expected time O(n) (worst-case O(n log

            .putAll('c', Arrays.asList('h', 'e', 'r', 'r', 'y'))
            .build();
    CollectorTester.of(collector, equivalence)
        .expectCollects(empty)
        .expectCollects(filled, "banana", "apple", "carrot", "asparagus", "cherry");
  }

  public void testEmptyMultimapReads() {
    Multimap<String, Integer> multimap = ImmutableListMultimap.of();
    assertFalse(multimap.containsKey("foo"));

            .putAll('c', Arrays.asList('h', 'e', 'r', 'r', 'y'))
            .build();
    CollectorTester.of(collector, equivalence)
        .expectCollects(empty)
        .expectCollects(filled, "banana", "apple", "carrot", "asparagus", "cherry");
  }

  public void testEmptyMultimapReads() {
    Multimap<String, Integer> multimap = ImmutableSetMultimap.of();
    assertFalse(multimap.containsKey("foo"));

    Helpers.testComparator(
        comparator,
        ImmutableList.of(
            "applesauce",
            "apricot",
            "artichoke",
            "banality",
            "banana",
            "banquet",
            "tangelo",
            "tangerine"));
    reserializeAndAssert(comparator);
  }

  public void testCompound_instance() {

    Helpers.testComparator(
        comparator,
        ImmutableList.of(
            "applesauce",
            "apricot",
            "artichoke",
            "banality",
            "banana",
            "banquet",
            "tangelo",
            "tangerine"));
    reserializeAndAssert(comparator);
  }

  public void testCompound_instance() {

   *
   * <p>Example:
   *
   * <pre>{@code
   * static final ListMultimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(
   *             toMultimap(
   *                  str -> str.charAt(0),
   *                  str -> str.substring(1),

   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableListMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableListMultimap.Builder<Character, String>()
   *         .put('b', "anana")
   *         .putAll('a', "pple", "sparagus")

    filled.putAll('c', Arrays.asList('h', 'e', 'r', 'r', 'y'));
    CollectorTester.of(collector, equivalence)
        .expectCollects(empty)
        .expectCollects(filled, "banana", "apple", "carrot", "asparagus", "cherry");
  }

  @SuppressWarnings("deprecation")
  public void testUnmodifiableListMultimapShortCircuit() {
    ListMultimap<String, Integer> mod = ArrayListMultimap.create();