public ApplicationBuilder monitor(MonitorConfig monitor) {
        this.monitor = monitor;
        return getThis();
    }
@Test
    void monitor() {
        MonitorConfig monitor = new MonitorConfig("monitor-addr");
        ApplicationBuilder builder = new ApplicationBuilder();
        builder.monitor(monitor);
        Assertions.assertSame(monitor, builder.build().getMonitor());
        Assertions.assertEquals("monitor-addr", builder.build().getMonitor().getAddress());
    }