out.write(buf, off, len);
      return true;
    }

    @Override
    public byte[] getResult() {
      return out.toByteArray();
    }
  }

  public void testByteProcessorStopEarly() throws IOException {
    byte[] array = newPreFilledByteArray(10000);
    assertEquals(
        (Integer) 42,
        ByteStreams.readBytes(
            new ByteArrayInputStream(array),