cloned this project and try to save files to local disk, but when using filebox.toFile, it throws out the exception.

code:
var filebox = await message.toFileBox();
await filebox.toFile();

I saw the discussion: huan/file-box#50
but I didn't find solution, it just said we need to save it in first use.
but this is the top thing I can do, just in on('message') function.

anyway to work around?