return Indexed.this;
        }
      };
    }
  }

  public static <E> Builder<E> builder() {
    return new Builder<E>();
  }

  public static <E> Builder<E> builderWithExpectedSize(int size) {
    return new Builder<E>(size);
  }

  public static class Builder<E> extends ImmutableCollection.Builder<E> {
    // accessed directly by ImmutableSortedSet
    final ArrayList<E> contents;