docs: private static int checkIndexOf(final String str, final int strStartIndex, final String search) {
          final int endIndex = str.length() - search.length();
          if (endIndex >= strStartIndex) {
              for (int i = strStartIndex; i <= endIndex; i++) {
                  if (checkRegionMatches(str, i, search)) {
                      return i;
                  }
              }
          }
          return -1;
      }