@Override
  Hasher putBoolean(boolean b);

  @CanIgnoreReturnValue
  @Override
  Hasher putChar(char c);

  /**
   * Equivalent to processing each {@code char} value in the {@code CharSequence}, in order. In
   * other words, no character encoding is performed; the low byte and high byte of each {@code
   * char} are hashed directly (in that order). The input must not be updated while this method is
   * in progress.
   *

     */
    public static char[] addAll(final char[] a, final char[] b) {
        if (a == null) {
            return b;
        }
        if (b == null) {
            return a;
        }
        if (a.length == 0) {
            return b;
        }
        if (b.length == 0) {
            return a;
        }
        final char[] array = (char[]) Array.newInstance(char.class, a.length + b.length);

    /**
     * Detail/bullet point icon.
     */
    DETAIL('•', "-"),

    /**
     * Action/arrow icon.
     */
    ACTION('→', ">");

    private final char unicodeChar;
    private final String asciiFallback;

    ConsoleIcon(char unicodeChar, String asciiFallback) {
        this.unicodeChar = unicodeChar;
        this.asciiFallback = asciiFallback;
    }

    /**

    // Exhaustively check all mappings (an int index avoids wrapping).
    for (int n = 0; n < replacementArray.length; n++) {
      char c = (char) n;
      String expected = map.get(c);
      if (expected == null) {
        assertThat(replacementArray[n]).isNull();
      } else {
        assertThat(new String(replacementArray[n])).isEqualTo(expected);
      }
    }
  }

            break;
        default:
            break;
        }
        return OptionalEntity.empty();
    }

    /**
     * Create a char mapping item.
     * @param form The create form.
     * @param hook The error hook.
     * @return An optional entity of a char mapping item.
     */
    protected OptionalEntity<CharMappingItem> createCharMappingItem(final CreateForm form, final VaErrorHook hook) {
        try {

      chars.add(randomNonAlpha());
    }
    Collections.shuffle(chars, random);
    char[] array = Chars.toArray(chars);
    this.testString = new String(array);
  }

  private char randomAlpha() {
    return ALPHA.charAt(random.nextInt(ALPHA.length()));
  }

  private char randomNonAlpha() {
    return NONALPHA.charAt(random.nextInt(NONALPHA.length()));
  }

  @Benchmark

        assertEquals(testStringTrue.length() + 1, unicodeStringTrue.buffer.length, "Buffer length should include zterm");
        for (int i = 0; i < testStringTrue.length(); i++) {
            assertEquals(testStringTrue.charAt(i), (char) unicodeStringTrue.buffer[i], "Character mismatch");
        }
        assertEquals(0, unicodeStringTrue.buffer[testStringTrue.length()], "Last character should be zero");

        // Test with a non-empty string and zterm = false

    @Override
    MessageBuilder append(char c);

    /**
     * Append content to the message buffer.
     *
     * @param value the content to append
     * @param offset the index of the first {@code char} to append
     * @param len the number of {@code char}s to append
     * @return the current builder
     */
    @Nonnull
    default MessageBuilder a(char[] value, int offset, int len) {

    assertThat(expected).hasMessageThat().isEqualTo(msg);
  }

  public void testBadArguments_plusforspace() {
    // space can be a safe char if plusForSpace is false
    PercentEscaper unused = new PercentEscaper(" ", false);

    // space cannot be a safe char is plusForSpace is true
    String msg = "plusForSpace cannot be specified when space is a 'safe' character";
    IllegalArgumentException expected =

   */
  private static char[] growBuffer(char[] dest, int index, int size) {
    if (size < 0) { // overflow - should be OutOfMemoryError but GWT/j2cl don't support it
      throw new AssertionError("Cannot increase internal buffer any further");
    }
    char[] copy = new char[size];
    if (index > 0) {
      System.arraycopy(dest, 0, copy, 0, index);
    }