val filesDir = _files.getFilesDir()
val file = _files.buildFile {
    setPath(filesDir, "tmp/aaa.txt")
}
file.writeText("hello world", "UTF-8")
val dest = _files.buildFile {
    setPath(filesDir, "tmp/bbb.txt")
}
_console.log(file.renameTo(dest))
_console.log(file.exists())
_console.log(dest.exists())
file.delete()
dest.delete()