let filesDir = $files.getFilesDir()
let file = $files.buildFile((fileBuilder) => {
    fileBuilder.setPath(filesDir, "tmp/aaa.txt")
})
file.writeText("hello world", "UTF-8")
let dest = $files.buildFile((fileBuilder) => {
    fileBuilder.setPath(filesDir, "tmp/bbb.txt")
})
$console.log(file.renameTo(dest))
$console.log(file.exists())
$console.log(dest.exists())
file.delete()
dest.delete()