private val delegate = object : NSObject(), UIDocumentPickerDelegateProtocol, UINavigationControllerDelegateProtocol {

    override fun documentPicker(
        controller: UIDocumentPickerViewController,
        didPickDocumentAtURL: NSURL
    ) {
        val fileNsData = didPickDocumentAtURL
        onDocumentPicked()
    }

    override fun documentPickerWasCancelled(controller: UIDocumentPickerViewController) {
        controller.dismissViewControllerAnimated(true, null)
    }
}