return Promise<URL> { resolve, reject, progress in
    Alamofire.download(escapedUrl, to: destination)
        .downloadProgress { downloadProgress in // downloadProgress is Progress class
            // let currentProgress = Float(downloadProgress.completedUnitCount) / Float(downloadProgress.totalUnitCount)
            // progress(currentProgress)
            progress(downloadProgress) // <- should be able to write like this
        }
        .response { response in
            ...
        }
}