private ProgressObservable progress = new DefaultProgress(-1, _("instanceUpdater.preparingUpdate"));
public Updater(@NonNull Launcher launcher, @NonNull Instance instance) {
super(launcher);
this.installer = new Installer(launcher.getInstallerDir());
this.launcher = launcher;
this.instance = instance;
librarySources.add(launcher.propUrl("librariesSource"));
assetsSources.add(launcher.propUrl("assetsSource"));