docs: public static boolean containsIgnoreCase(final CharSequence str, final CharSequence searchStr) {
          if (str == null || searchStr == null) {
              return false;
          }
          final int len = searchStr.length();
          final int max = str.length() - len;
          for (int i = 0; i <= max; i++) {
              if (CharSequenceUtils.regionMatches(str, true, i, searchStr, 0, len)) {
                  return true;
              }
          }
          return false;
      }