如何在iOS中将数据类型转换为其他类型？

Question

我需要将typealias到CloudKit保存为类型Bytes的字段。

我能够成功地将typealias转换为类型Data的对象。我该如何将Data类型的对象转换为typealias的对象？

typealias NotificationIdentifiers = [[String]?]

var notificationIdentifiers: NotificationIdentifiers = [nil, [UUID().uuidString], [UUID().uuidString], [UUID().uuidString], [UUID().uuidString], [UUID().uuidString], [UUID().uuidString]]
let unsafeNIPointer: UnsafePointer<NotificationIdentifiers> = UnsafePointer<NotificationIdentifiers>(&notificationIdentifiers)
let unsafeNIBufferPointer: UnsafeBufferPointer<NotificationIdentifiers> = UnsafeBufferPointer<NotificationIdentifiers>(start: unsafeNIPointer, count: 1)
let dataNotificationIdentifiers: Data = Data(buffer: unsafeNIBufferPointer)