Send custom event from worker(-thread) to MainWindow in order to update

progress bar.

mainwindow.h

@@ -13,6 +13,9 @@ QT_END_NAMESPACE
 class MainWindow : public QMainWindow {
     Q_OBJECT
 
+protected:
+    void customEvent(QEvent *event) override;
+
 public:
     MainWindow(Worker *worker, QWidget *parent = nullptr);
     ~MainWindow();
@@ -20,7 +23,6 @@ public:
 public slots:
     void onAppendText(QString, QString);
     void onShowErrorMessage(QString, QString);
-    void onSetProgress(quint8);
     void onStopStartTimer();
     void onRestartExitTimer();
     void onEnableExit();