private void testThreshold(
      int fileThreshold, int dataSize, boolean singleByte, boolean resetOnFinalize)
      throws IOException {
    byte[] data = newPreFilledByteArray(dataSize);
    FileBackedOutputStream out = new FileBackedOutputStream(fileThreshold, resetOnFinalize);
    ByteSource source = out.asByteSource();
    int chunk1 = min(dataSize, fileThreshold);
    int chunk2 = dataSize - chunk1;