@Override
    public void notifyClientDisconnected(final String clientID, final String username) {
        for (final InterceptHandler handler : this.handlers.get(InterceptDisconnectMessage.class)) {
            LOG.debug("Notifying MQTT client disconnection to interceptor. CId={}, username={}, interceptorId={}",
                clientID, username, handler.getID());
            executor.execute(() -> handler.onDisconnect(new InterceptDisconnectMessage(clientID, username)));
        }
    }
@Test
    public void testNotifyClientDisconnected() throws Exception {
        interceptor.notifyClientDisconnected("cli1234", "cli1234");
        interval();
        assertEquals(50, n.get());
    }