void handleStart(Exchange exchange, MetricRegistry registry, String metricsName) {
        String propertyName = getPropertyName(metricsName);
        Timer.Context context = getTimerContextFromExchange(exchange, propertyName);
        if (context == null) {
            Timer timer = registry.timer(metricsName);
            context = timer.time();
            exchange.setProperty(propertyName, context);
        } else {
            LOG.warn("Timer \"{}\" already running", metricsName);
        }
    }
@Test
    public void testHandleStartAlreadyRunning() {
        when(exchange.getProperty(PROPERTY_NAME, Timer.Context.class)).thenReturn(context);
        producer.handleStart(exchange, registry, METRICS_NAME);
        inOrder.verify(exchange, times(1)).getProperty(PROPERTY_NAME, Timer.Context.class);
        inOrder.verifyNoMoreInteractions();
    }