@ParametricNullness private final V left;
    @ParametricNullness private final V right;

    static <V extends @Nullable Object> ValueDifference<V> create(
        @ParametricNullness V left, @ParametricNullness V right) {
      return new ValueDifferenceImpl<>(left, right);
    }

    private ValueDifferenceImpl(@ParametricNullness V left, @ParametricNullness V right) {
      this.left = left;
      this.right = right;
    }

      UnmodifiableIterator<T> iterator) {
    return checkNotNull(iterator);
  }

  /**
   * Returns the number of elements remaining in {@code iterator}. The iterator will be left
   * exhausted: its {@code hasNext()} method will return {@code false}.
   */
  public static int size(Iterator<?> iterator) {
    long count = 0L;
    while (iterator.hasNext()) {
      iterator.next();

      return uid;
    }

    @Override
    public int compare(@CheckForNull Object left, @CheckForNull Object right) {
      if (left == right) {
        return 0;
      } else if (left == null) {
        return -1;
      } else if (right == null) {
        return 1;
      }
      int leftCode = identityHashCode(left);
      int rightCode = identityHashCode(right);
      if (leftCode != rightCode) {

      System.setProperty(PATH_SEPARATOR.key(), oldPathSeparator);
      System.setProperty(JAVA_CLASS_PATH.key(), oldClassPath);
    }
  }

  private static boolean contentEquals(URL left, URL right) throws IOException {
    return Resources.asByteSource(left).contentEquals(Resources.asByteSource(right));
  }

  private static class Nested {}


  public void testNulls() throws IOException {

  }

  /**
   * Returns a view of a multimap where each value is transformed by a function. All other
   * properties of the multimap, such as iteration order, are left intact. For example, the code:
   *
   * <pre>{@code
   * Multimap<String, Integer> multimap =
   *     ImmutableSetMultimap.of("a", 2, "b", -3, "b", -3, "a", 4, "c", 6);