* elements and to build again.
   *
   * @since 2.0
   */
  public static class Builder<E> extends ImmutableCollection.ArrayBasedBuilder<E> {
    @VisibleForTesting @CheckForNull @Nullable Object[] hashTable;
    private int hashCode;

    /**
     * Creates a new builder. The returned builder is equivalent to the builder generated by {@link

   * multiple lists in series. Each new list contains all the elements of the ones created before
   * it.
   *
   * @since 2.0
   */
  public static final class Builder<E> extends ImmutableCollection.ArrayBasedBuilder<E> {
    /**
     * Creates a new builder. The returned builder is equivalent to the builder generated by {@link
     * ImmutableList#builder}.
     */
    public Builder() {