* Here's an outline of the overall design.
   *
   * The map variable contains the collection of values associated with each
   * key. When a key-value pair is added to a multimap that didn't previously
   * contain any values for that key, a new collection generated by
   * createCollection is added to the map. That same collection instance
   * remains in the map as long as the multimap has any values for the key. If

    this.itemReporter = checkNotNull(itemReporter);
  }

  /**
   * Adds {@code equalityGroup} with objects that are supposed to be equal to each other and not
   * equal to any other equality groups added to this tester.
   *
   * <p>The {@code @Nullable} annotations on the {@code equalityGroup} parameter imply that the
   * objects, and the array itself, can be null. That is for programmer convenience, when the

            protected N computeNext() {
              while (nodeConnections.hasNext()) {
                NodeConnection<N> nodeConnection = nodeConnections.next();
                boolean added = seenNodes.add(nodeConnection.node);
                if (added) {
                  return nodeConnection.node;
                }
              }
              return endOfData();
            }
          };
        }

  }

  @Override
  <E extends Comparable<E>> Builder<E> builder() {
    return ImmutableSet.builder();
  }

  @Override
  int getComplexBuilderSetLastElement() {
    return LAST_COLOR_ADDED;
  }

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(ImmutableSet.of(), ImmutableSet.of())
        .addEqualityGroup(ImmutableSet.of(1), ImmutableSet.of(1), ImmutableSet.of(1, 1))

    latch.countDown();

    exec.shutdown();
    exec.awaitTermination(100, MILLISECONDS);
  }

  /**
   * Tests that all listeners complete, even if they were added before or after the future was
   * finishing. Also acts as a concurrency test to make sure the locking is done correctly when a
   * future is finishing so that no listeners can be lost.
   */

 *
 * <p>When iterating through the collections supplied by this class, the ordering of values for a
 * given key agrees with the order in which the values were added.
 *
 * <p>This multimap allows duplicate key-value pairs. After adding a new key-value pair equal to an
 * existing key-value pair, the {@code ArrayListMultimap} will contain entries for both the new
 * value and the old value.

  // here to provide error messages.
  // TODO(user): Some Strings used in the subclasses can be added as static Strings
  // here too.
  static final String ERROR_MODIFIABLE_SET = "Set returned is unexpectedly modifiable";
  static final String ERROR_SELF_LOOP = "self-loops are not allowed";
  static final String ERROR_ADDED_SELF_LOOP = "Should not be allowed to add a self-loop edge.";

    Builder<K, V> combine(Builder<K, V> builder) {
      entries.addAll(builder.entries);
      return this;
    }

    /**
     * Returns an {@code ImmutableRangeMap} containing the associations previously added to this
     * builder.
     *
     * @throws IllegalArgumentException if any two ranges inserted into this builder overlap
     */
    public ImmutableRangeMap<K, V> build() {

    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertSize(3);
  }

  public void testEquals() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    // We know that we have only added non-null Characters.
    Table<String, Integer, Character> hashCopy =
        HashBasedTable.create((Table<String, Integer, ? extends Character>) table);

    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertSize(3);
  }

  public void testEquals() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    // We know that we have only added non-null Characters.
    Table<String, Integer, Character> hashCopy =
        HashBasedTable.create((Table<String, Integer, ? extends Character>) table);