public synchronized void disConnect() {
        if (refreshFuture != null) {
            refreshFuture.cancel(true);
            refreshFuture = null;
        }
        if (channel != null) {
            channel = null;
        }
    }
@Test
    void testDisconnect() {
        FrameworkModel frameworkModel = new FrameworkModel();
        DubboCertManager certManager = new DubboCertManager(frameworkModel);
        ScheduledFuture scheduledFuture = Mockito.mock(ScheduledFuture.class);
        certManager.refreshFuture = scheduledFuture;
        certManager.disConnect();
        Assertions.assertNull(certManager.refreshFuture);
        Mockito.verify(scheduledFuture, Mockito.times(1)).cancel(true);

        certManager.channel = Mockito.mock(Channel.class);
        certManager.disConnect();
        Assertions.assertNull(certManager.channel);

        frameworkModel.destroy();
    }