My Download Manager app is a real project which will manage download tasks. It allow users to start download a file, pause or resume the download task, and stop a download task. In tutorial 1, I already show you all the basic functions, such as starting a download, pause, resume and stop it. However, these basic functions are really not enough. For example, if I pause the download task and quit the app, the app will lose all downloaded data.
The only solution for that is saving the downloaded data into iOS device locally when we pause the download data. So we will not lose the data even we quit the app. If we want to resume the download task, we can load the data from where we store it locally and continue to download the rest of it.