I’m working with UIDocument to store a PDF file. This is code I use for saving a file.

Firstly, I created a document with URL.

let document = UIDocument(fileURL: url)

Second, I opened a document.

document.open(completionHandler: { (success) in
            if success {
                // open successfully
            }
        })

And finally, I saved the document.

document.close(completionHandler: { (success) in
            if success {
                document.save(to: url,
                              for: .forOverwriting,
                              completionHandler: { (success) in
                    if success {
                        print("Saved file successfully")
                    }
                })
            } 
        })

This code works well with a small file size. But if it’s a large file like 100MB, it takes around 2-5 minutes to save the file. Is there a way to save file with the changes only? Or create an auto save function triggered whenever the user edit the file?

I tried to find other UIDocument.SaveOperation but seems there’re only 2 options: create a new one or overwrite the old file which doesn’t match my expectation.