code: @Benchmark void reverseNoSurrogates(int reps) {
      final int length = Math.min(this.length, MIN_SURROGATE);
      StringBuilder sb = new StringBuilder();
      for (int j = 0; j < length; j++) {
        sb.appendCodePoint(j);
      }
      for (int i = 0; i < reps; i++) {
        for (int j = 0; j < 4; j++) {
          sb.reverse();
        }
        if (sb.codePointAt(0) > MIN_SURROGATE)
          throw new Error();
      }
    }
docs: Times .reverse() when no surrogates are present.