Download von Google Drive

private fun downloadFile(realFileId: String): ByteArrayOutputStream? {
    //   getString(R.string.api_key)  --> requestInitializer

    val drive = Drive.Builder(
        NetHttpTransport(),
        JacksonFactory.getDefaultInstance(),
        null// <-- requestInitializer
    )
        .setApplicationName(getString(R.string.app_name))
        .build()

    return try {
        val outputStream: OutputStream = ByteArrayOutputStream()
        drive.files()[realFileId]
            .executeMediaAndDownloadTo(outputStream)
        outputStream as ByteArrayOutputStream
    } catch (e: Exception) {
        Log.i("x", "$e")
        null
    }
}