*
   * <pre>{@code
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableSetMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableSetMultimap.Builder<Character, String>()

      InternetDomainName.from("j\u00f8rpeland.no");
  private static final InternetDomainName PUNYCODE_EXAMPLE =
      InternetDomainName.from("xn--jrpeland-54a.no");

  /** The Greek letter delta, used in unicode testing. */
  private static final String DELTA = "\u0394";

  /** A domain part which is valid under lenient validation, but invalid under strict validation. */

   *
   * <pre>{@code
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableListMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableListMultimap.Builder<Character, String>()

   *
   * <pre>{@code
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableSetMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableSetMultimap.Builder<Character, String>()

      InternetDomainName.from("j\u00f8rpeland.no");
  private static final InternetDomainName PUNYCODE_EXAMPLE =
      InternetDomainName.from("xn--jrpeland-54a.no");

  /** The Greek letter delta, used in unicode testing. */
  private static final String DELTA = "\u0394";

  /** A domain part which is valid under lenient validation, but invalid under strict validation. */

     * for this entry is one, this is simply the string representation of the corresponding element.
     * Otherwise, it is the string representation of the element, followed by the three characters
     * {@code " x "} (space, letter x, space), followed by the count.
     */
    @Override
    String toString();
  }

  // Comparison and hashing

  /**

  private static final CharMatcher DIGIT_MATCHER = CharMatcher.inRange('0', '9');

  private static final CharMatcher LETTER_MATCHER =
      CharMatcher.inRange('a', 'z').or(CharMatcher.inRange('A', 'Z'));

  private static final CharMatcher PART_CHAR_MATCHER =
      DIGIT_MATCHER.or(LETTER_MATCHER).or(DASH_MATCHER);

  /**
   * Helper method for {@link #validateSyntax(List)}. Validates that one part of a domain name is

   *
   * <pre>{@code
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableListMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableListMultimap.Builder<Character, String>()

    /*
     * The striding algorithm works roughly as follows: it is universally the case that
     * CRC(x ^ y) == CRC(x) ^ CRC(y).  The approach we take is to break the message as follows,
     * with each letter representing a 4-byte word: ABCDABCDABCDABCD... and to calculate
     * CRC(A000A000A000...), CRC(0B000B000B...), CRC(00C000C000C...), CRC(000D000D000D...)