How to retrieve AVDepthData from AVCapturePhoto filedatarepresentation?

I have successfully saved image data from avcapturephoto using

        if let filedata = photo.fileDataRepresentation() ,
            let path = documentDirectoryPath()?.appendingPathComponent("item.data") {
                try? filedata.write(to: path)
            }

for reading the image, I can use this

let url = Bundle.main.url(forResource: "item", withExtension: "data")!

let fileDataRepresentation = try Data(contentsOf: url as URL)
let uiImage = UIImage(data:fileDataRepresentation)

How can I read the saved depth data? will it be in AVDepthData format?

AVDepthData(something: Data) // how to do this?