// which means they are treated as pairs of safe characters).
    builder.setSafeRange(Character.MIN_VALUE, '\uFFFD');
    // Unsafe characters are replaced with the Unicode replacement character.
    builder.setUnsafeReplacement("\uFFFD");

    /*
     * Except for \n, \t, and \r, all ASCII control characters are replaced with the Unicode
     * replacement character.
     *

 * <td>bytes</td>
 * <td>characters</td>
 * <td>bytes, characters</td>
 * <td>characters</td>
 * </tr>
 * <tr>
 * <th>{@link Reader}</th>
 * <td>characters</td>
 * <td>characters</td>
 * <td>characters</td>
 * <td>characters</td>
 * </tr>
 * <tr>
 * <th>{@link File}</th>
 * <td>bytes</td>
 * <td>characters</td>
 * <td>bytes, characters</td>
 * <td>characters</td>
 * </tr>
 * <tr>

   *
   * @param replacementMap a map of characters to their escaped representations
   * @param safeMin the lowest character value in the safe range
   * @param safeMax the highest character value in the safe range
   * @param unsafeReplacement the default replacement for unsafe characters or null if no default
   *     replacement is required
   */
  protected ArrayBasedUnicodeEscaper(

   * <p>Note however that if your escaper does not escape characters in the supplementary range, you
   * should either continue to validate the correctness of any surrogate characters encountered or
   * provide a clear warning to users that your escaper does not validate its input.
   *
   * <p>See {@link com.google.common.net.PercentEscaper} for an example.
   *
   * @param csq a sequence of characters

   * <p>Note however that if your escaper does not escape characters in the supplementary range, you
   * should either continue to validate the correctness of any surrogate characters encountered or
   * provide a clear warning to users that your escaper does not validate its input.
   *
   * <p>See {@link com.google.common.net.PercentEscaper} for an example.
   *
   * @param csq a sequence of characters

  }

  /**
   * Parses a trie node and returns the number of characters consumed.
   *
   * @param stack The prefixes that precede the characters represented by this node. Each entry of
   *     the stack is in reverse order.
   * @param encoded The serialized trie.
   * @param start An index in the encoded serialized trie to begin reading characters from.
   * @param builder A map builder to which all entries will be added.

    // Empty
    assertWellFormed();
    // One-byte characters, including control characters
    assertWellFormed(0x00, 0x61, 0x62, 0x63, 0x7F); // "\u0000abc\u007f"
    // Two-byte characters
    assertWellFormed(0xC2, 0xA2, 0xC2, 0xA2); // "\u00a2\u00a2"
    // Three-byte characters
    assertWellFormed(0xc8, 0x8a, 0x63, 0xc8, 0x8a, 0x63); // "\u020ac\u020ac"
    // Four-byte characters
    // "\u024B62\u024B62"

    }

    /**
     * Sets the replacement string for any characters outside the 'safe' range that have no explicit
     * replacement. If {@code unsafeReplacement} is {@code null} then no replacement will occur, if
     * it is {@code ""} then the unsafe characters are removed from the output.
     *
     * @param unsafeReplacement the string to replace unsafe characters
     * @return the builder instance
     */

        // Test toString with buffer containing non-printable characters or special unicode
        String unicodeChars = "你好世界"; // "Hello World" in Chinese
        UnicodeString unicodeStringChinese = new UnicodeString(unicodeChars, false);
        assertEquals(unicodeChars, unicodeStringChinese.toString(), "toString should handle unicode characters correctly");

 * href="http://www.unicode.org/glossary/#BMP_character">BMP characters</a>. It does not understand
 * <a href="http://www.unicode.org/glossary/#supplementary_code_point">supplementary Unicode code
 * points</a> in the range {@code 0x10000} to {@code 0x10FFFF} which includes the majority of
 * assigned characters, including important CJK characters and emoji.
 *
 * <p>Supplementary characters are <a