code: @Nonnull
      public static String escapeXML(CharSequence s) {
          // double quote -- quot
          // ampersand -- amp
          // less than -- lt
          // greater than -- gt
          // apostrophe -- apos
          StringBuilder sb = new StringBuilder(s.length() * 2);
          for (int i = 0; i < s.length();) {
              int codePoint = Character.codePointAt(s, i);
              if (codePoint == '<') {
                  sb.append(LT);
              } else if (codePoint == '>') {
                  sb.append(GT);
              } else if (codePoint == '\"') {
                  sb.append(QUOT);
              } else if (codePoint == '&') {
                  sb.append(AMP);
              } else if (codePoint == '\'') {
                  sb.append(APOS);
              } else {
                  sb.appendCodePoint(codePoint);
              }
              i += Character.charCount(codePoint);
          }
          return sb.toString();
      }
docs: Escapes a character sequence so that it is valid XML.
  
  @param s
  The character sequence.
  @return The escaped version of the character sequence.