immutableCell("two", "dos", 2),
            immutableCell("three", "tres", 3));
  }

  public void testToTableNullMerge() {
    // TODO github.com/google/guava/issues/6824 - the null merge feature is not compatible with the
    // current nullness annotation of the mergeFunction parameter. Work around with casts.
    BinaryOperator<@Nullable Integer> mergeFunction = (v1, v2) -> null;

          "stanford.edu",
          "state.ca.us",
          "www.state.ca.us",
          "state.ca.us",
          "pvt.k12.ca.us",
          "www.rave.ca.",
          "cnn.ca",
          "ledger-enquirer.com",
          "it-trace.ch",
          "cool.dk",
          "cool.co.uk",
          "cool.de",
          "cool.es",
          "cool\uFF61fr", // Alternate dot character
          "cool.nl",

        for (int i = 0; i < array.length; i++) {
          array[i] = counter.getAndIncrement();
        }
        builder.addAll(ImmutableLongArray.copyOf(array));
      }
    },
    ADD_LARGER_ARRAY {
      @Override
      void doIt(ImmutableLongArray.Builder builder, AtomicLong counter) {
        long[] array = new long[RANDOM.nextInt(200) + 200];
        for (int i = 0; i < array.length; i++) {

        for (int i = 0; i < array.length; i++) {
          array[i] = counter.getAndIncrement();
        }
        builder.addAll(ImmutableDoubleArray.copyOf(array));
      }
    },
    ADD_LARGER_ARRAY {
      @Override
      void doIt(ImmutableDoubleArray.Builder builder, AtomicInteger counter) {
        double[] array = new double[RANDOM.nextInt(200) + 200];
        for (int i = 0; i < array.length; i++) {

      this.mergeFunction = mergeFunction;
    }

    void put(K key, V value) {
      if (map == null) {
        map = new EnumMap<>(singletonMap(key, value));
      } else {
        map.merge(key, value, mergeFunction);
      }
    }

    EnumMapAccumulator<K, V> combine(EnumMapAccumulator<K, V> other) {
      if (this.map == null) {
        return other;
      } else if (other.map == null) {

       * fastest (more than twice as fast as the Java implementation, vs ~1.5x with non-final static
       * fields, on x86_32) under the Hotspot server compiler. The reason is obviously that the
       * non-final fields need to be reloaded inside the loop.
       *
       * And, no, defining (final or not) local variables out of the loop still isn't as good

  }

  // enum singleton pattern
  private enum ToStringFunction implements Function<Object, String> {
    INSTANCE;

    @Override
    public String apply(Object o) {
      checkNotNull(o); // eager for GWT.
      return o.toString();
    }

    @Override
    public String toString() {
      return "Functions.toStringFunction()";
    }
  }

  /**
   * Returns the identity function.
   *

 *
 * <p>Unlike {@code java.util.HashSet}, iteration is only proportional to the actual {@code size()},
 * which is optimal, and <i>not</i> the size of the internal hashtable, which could be much larger
 * than {@code size()}. Furthermore, this structure only depends on a fixed number of arrays; {@code
 * add(x)} operations <i>do not</i> create objects for the garbage collector to deal with, and for

   * Returns {@code false} if {@code n} is zero, one, or a composite number (one which <i>can</i> be
   * factored into smaller positive integers).
   *
   * <p>To test larger numbers, use {@link LongMath#isPrime} or {@link BigInteger#isProbablePrime}.
   *
   * @throws IllegalArgumentException if {@code n} is negative
   * @since 20.0
   */
  @GwtIncompatible // TODO

  }

  private static <K, V> ImmutableSetMultimap<K, V> copyOf(
      Multimap<? extends K, ? extends V> multimap,
      @CheckForNull Comparator<? super V> valueComparator) {
    checkNotNull(multimap); // eager for GWT
    if (multimap.isEmpty() && valueComparator == null) {
      return of();
    }

    if (multimap instanceof ImmutableSetMultimap) {