/** Start processing the images for text recognition */
    fun startProcessing(onFinish: (List<String>) -> Unit) {
        val result = mutableListOf<String>()

        Log.d(TAG, "Images to process: ${taskList.size}")

        if (taskList.isEmpty()) { return }

        taskList.forEach { image ->
            Log.i(TAG, "Start")
            val startTime = Date().time

            detector.processImage(image) // runs asynchronous
                .addOnSuccessListener { firebaseVisionText ->
                    val elapsedMilliseconds = Date().time - startTime
                    Log.i(TAG, "Text recognition took ${elapsedMilliseconds / 1000} seconds")
                    Log.d(TAG, "Processing is running in [${Thread.currentThread().name}] thread")
                    Log.i(TAG, "list size: ${taskList.size}")
                    Log.e(TAG, firebaseVisionText.text)
                    result.add(firebaseVisionText.text)
                }
                .addOnFailureListener { e ->
                    Log.e(TAG, "Processing image failed. ${e.cause}")
                }.addOnCompleteListener {
                    Log.i(TAG, "Completed!")
                }

        }
        Log.i(TAG, "After for loop")
        // how to wait for processing multiple images in taskList
        onFinish(result)
    }