CheckFileSizesExample.swift

    func checkFileSizesDemo() {
        guard let docDir = FileManager.default.urls(for: .documentDirectory,
                                                    in: .userDomainMask).first else { 
            return 
        }

        do {
            let testDir = docDir.appendingPathComponent("test")
            try FileManager.default.createDirectory(at: testDir, 
                                                    withIntermediateDirectories: true, 
                                                    attributes: nil)

            let textURL = testDir.appendingPathComponent("text_size_test")
            let text = """
Let us always meet each other with smile, for the smile is the beginning of love.
Mother Teresa
"""
            try text.write(to: textURL, atomically: true, encoding: .utf8)

            if let image = UIImage(named: "swift-og") {
                let pngURL = testDir.appendingPathComponent("png_size_test")
                let pngData = image.pngData()
                try pngData?.write(to: pngURL, options: [.atomic])

                let jpgURL = testDir.appendingPathComponent("jpg_size_test")
                let jpgData = image.jpegData(compressionQuality: 1.0)
                try jpgData?.write(to: jpgURL, options: [.atomic])
            }
            
            FileManager.default.checkFileSizes(in: docDir)
          } catch {
            print("error: \(error)")
        }
    }