@J2ktIncompatible
  @GwtIncompatible // serialization
  private static Object reserialize(Object object) throws Exception {
    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    new ObjectOutputStream(bytes).writeObject(object);
    return new ObjectInputStream(new ByteArrayInputStream(bytes.toByteArray())).readObject();
  }

  private static final LittleEndianBytes byteArray;

  /**
   * Load 8 bytes into long in a little endian manner, from the substring between position and
   * position + 8. The array must have at least 8 bytes from offset (inclusive).
   *
   * @param input the input bytes
   * @param offset the offset into the array at which to start
   * @return a long of a concatenated 8 bytes
   */
  static long load64(byte[] input, int offset) {

  @J2ktIncompatible
  @GwtIncompatible // serialization
  private static Object reserialize(Object object) throws Exception {
    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    new ObjectOutputStream(bytes).writeObject(object);
    return new ObjectInputStream(new ByteArrayInputStream(bytes.toByteArray())).readObject();
  }

  /**
   * Creates a new instance that uses the given file threshold, and does not reset the data when the
   * {@link ByteSource} returned by {@link #asByteSource} is finalized.
   *
   * @param fileThreshold the number of bytes before the stream should switch to buffering to a file
   * @throws IllegalArgumentException if {@code fileThreshold} is negative
   */
  public FileBackedOutputStream(int fileThreshold) {
    this(fileThreshold, false);