@Override
  public HashCode hashString(CharSequence input, Charset charset) {
    if (charset.equals(UTF_8)) {
      int utf16Length = input.length();
      int h1 = seed;
      int i = 0;
      int len = 0;

      // This loop optimizes for pure ASCII.
      while (i + 4 <= utf16Length) {
        char c0 = input.charAt(i);
        char c1 = input.charAt(i + 1);
        char c2 = input.charAt(i + 2);