public Timer timer(String name) {
        return getOrAdd(name, MetricBuilder.TIMERS);
    }
@Test
    public void accessingACustomTimerRegistersAndReusesIt() {
        final MetricRegistry.MetricSupplier<Timer> supplier = () -> timer;
        final Timer timer1 = registry.timer("thing", supplier);
        final Timer timer2 = registry.timer("thing", supplier);

        assertThat(timer1)
                .isSameAs(timer2);

        verify(listener).onTimerAdded("thing", timer1);
    }