bufferHelper("no newlines at all", "no newlines at all");
    bufferHelper("two lines\nbut no newline at end", "two lines\n", "but no newline at end");
    bufferHelper(
        "\nempty first line\nno newline at end", "\n", "empty first line\n", "no newline at end");
    bufferHelper("three\rlines\rno newline at end", "three\r", "lines\r", "no newline at end");

    bufferHelper("no newlines at all", "no newlines at all");
    bufferHelper("two lines\nbut no newline at end", "two lines\n", "but no newline at end");
    bufferHelper(
        "\nempty first line\nno newline at end", "\n", "empty first line\n", "no newline at end");
    bufferHelper("three\rlines\rno newline at end", "three\r", "lines\r", "no newline at end");

    @Nonnull
    default MessageBuilder a(Object value) {
        return append(String.valueOf(value));
    }

    /**
     * Append newline to the message buffer.
     *
     * @return the current builder
     */
    @Nonnull
    default MessageBuilder newline() {
        return append(System.lineSeparator());
    }

    /**
     * Append formatted content to the buffer.

    @Override
    public Optional<Long> lengthIfKnown() {
      return Optional.of((long) seq.length());
    }

    /**
     * Returns an iterator over the lines in the string. If the string ends in a newline, a final
     * empty string is not included, to match the behavior of BufferedReader/LineReader.readLine().
     */
    private Iterator<String> linesIterator() {
      return new AbstractIterator<String>() {

        return this;
    }

    public Ansi a(StringBuffer value) {
        flushAttributes();
        builder.append(value);
        return this;
    }

    public Ansi newline() {
        flushAttributes();
        builder.append(System.lineSeparator());
        return this;
    }

    public Ansi format(String pattern, Object... args) {
        flushAttributes();

    int newSize = newEntryIndex + 1;
    int hash = smearedHash(object);
    int mask = hashTableMask();
    int tableIndex = hash & mask;
    int next = CompactHashing.tableGet(requireTable(), tableIndex);
    if (next == UNSET) { // uninitialized bucket
      if (newSize > mask) {
        // Resize and add new entry

        List<T> newList = null;
        for (int i = 0; i < list.size(); i++) {
            T oldT = list.get(i);
            T newT = modifer.apply(oldT);
            if (newT != oldT) {
                if (newList == null) {
                    newList = new ArrayList<>(list);
                }
                newList.set(i, newT);
            }
        }
        return newList;

        List<T> newList = Lists.newArrayList(scenario.strictlyOrderedList);
        Collections.reverse(newList);
        return new Scenario<T>(scenario.ordering.reverse(), newList, scenario.emptyArray);
      }
    },
    NULLS_FIRST {
      @Override
      <T extends @Nullable Object> Scenario<?> mutate(Scenario<T> scenario) {
        List<T> newList = Lists.newArrayList((T) null);

        List<T> newList = Lists.newArrayList(scenario.strictlyOrderedList);
        Collections.reverse(newList);
        return new Scenario<T>(scenario.ordering.reverse(), newList, scenario.emptyArray);
      }
    },
    NULLS_FIRST {
      @Override
      <T extends @Nullable Object> Scenario<?> mutate(Scenario<T> scenario) {
        List<T> newList = Lists.newArrayList((T) null);

    int newSize = newEntryIndex + 1;
    int hash = smearedHash(object);
    int mask = hashTableMask();
    int tableIndex = hash & mask;
    int next = CompactHashing.tableGet(requireTable(), tableIndex);
    if (next == UNSET) { // uninitialized bucket
      if (newSize > mask) {
        // Resize and add new entry