Custom events are processed only after the first ::processEvents

#include <QtGui>

class Object : public QObject {
    Q_OBJECT
public:
signals:
    void signal();

public:
    void emitSignal() { emit signal(); }
private slots:
    void slot() {
        qDebug("slot called");
    }
};

#include "main.moc"

int main(int argc, char **argv) {
  QApplication app(argc, argv);
  Object object;
  QObject::connect(&object, SIGNAL(signal()), &object, SLOT(slot()), Qt::QueuedConnection);
  object.emitSignal();
  qDebug("processEvents 1");
  QCoreApplication::processEvents();
  qDebug("processEvents 2");
  QCoreApplication::processEvents();
  object.emitSignal();;
  qDebug("processEvents 3");
  QCoreApplication::processEvents();
  return 0;
}