@Override
  public byte[] getBytes() {
    //todo handle unavailable content
    //if (!isAvailable()) throw new RuntimeException("content is not available");
    try {
      if (myContentId == UNAVAILABLE) return ArrayUtilRt.EMPTY_BYTE_ARRAY;
      return getFS().contentsToByteArray(myContentId);
    }
    catch (IOException e) {
      throw new RuntimeException("cannot get stored content", e);
    }
  }
@Override
  public byte[] getBytes()