/**
   * Shortcut for {@code newHasher().putBytes(input, off, len).hash()}. The implementation
   * <i>might</i> perform better than its longhand equivalent, but should not perform worse.
   *
   * @throws IndexOutOfBoundsException if {@code off < 0} or {@code off + len > bytes.length} or
   *     {@code len < 0}
   */
  HashCode hashBytes(byte[] input, int off, int len);

  /**

  public static ByteSourceFactory asSlicedByteSourceFactory(
      final ByteSourceFactory factory, final long off, final long len) {
    checkNotNull(factory);
    return new ByteSourceFactory() {
      @Override
      public ByteSource createSource(byte[] bytes) throws IOException {
        return factory.createSource(bytes).slice(off, len);
      }

      @Override
      public byte[] getExpected(byte[] bytes) {

          public Range<K> get(int index) {
            checkElementIndex(index, len);
            if (index == 0 || index == len - 1) {
              return ranges.get(index + off).intersection(range);
            } else {
              return ranges.get(index + off);
            }
          }

          @Override
          boolean isPartialView() {
            return true;
          }

   */
  private static Reader newNonBufferFillingReader(Reader reader) {
    return new FilterReader(reader) {
      @Override
      public int read(char[] cbuf, int off, int len) throws IOException {
        // if a buffer isn't being cleared correctly, this method will eventually start being called
        // with a len of 0 forever
        if (len <= 0) {

   */
  private static Reader newNonBufferFillingReader(Reader reader) {
    return new FilterReader(reader) {
      @Override
      public int read(char[] cbuf, int off, int len) throws IOException {
        // if a buffer isn't being cleared correctly, this method will eventually start being called
        // with a len of 0 forever
        if (len <= 0) {

      bufs.add(buf);
      int off = 0;
      while (off < buf.length) {
        // always OK to fill buf; its size plus the rest of bufs is never more than MAX_ARRAY_LEN
        int r = in.read(buf, off, buf.length - off);
        if (r == -1) {
          return combineBuffers(bufs, totalLen);
        }
        off += r;
        totalLen += r;
      }
    }

    ByteProcessor<byte[]> processor =
        new ByteProcessor<byte[]>() {
          int pos;

          @Override
          public boolean processBytes(byte[] buf, int off, int len) throws IOException {
            System.arraycopy(buf, off, processedBytes, pos, len);
            pos += len;
            return true;
          }

          @Override
          public byte[] getResult() {

            new ByteProcessor<Integer>() {
              @Override
              public boolean processBytes(byte[] buf, int off, int len) {
                assertThat(newPreFilledByteArray(8192))
                    .isEqualTo(Arrays.copyOfRange(buf, off, off + len));
                return false;
              }

              @Override
              public Integer getResult() {

      if (optionalUnslicedSize.isPresent()) {
        long unslicedSize = optionalUnslicedSize.get();
        long off = Math.min(offset, unslicedSize);
        return Optional.of(Math.min(length, unslicedSize - off));
      }
      return Optional.absent();
    }

    @Override
    public String toString() {

      limiter.acquire(); // #5
    }
    stopwatch.sleepMillis(4250); // #6, back to cold state (warmup period + repay last acquire)
    for (int i = 0; i < 11; i++) {
      limiter.acquire(); // #7, showing off the warmup starting from totally cold
    }

    // make sure the areas (times) remain the same, while permits are different
    assertEvents(
        "R0.00, R1.38, R1.13, R0.88, R0.63, R0.50, R0.50, R0.50", // #1