@Test
 public void test() {
   // by default, it's disabled
   assertFalse(AwsSdkMetrics.isDefaultMetricsEnabled());
   // won't be anble to enable unless the default impl library is on the classpath
   assertFalse(AwsSdkMetrics.enableDefaultMetrics());
   assertFalse(AwsSdkMetrics.isDefaultMetricsEnabled());
   assertSame(RequestMetricCollector.NONE, AwsSdkMetrics.getRequestMetricCollector());
   assertFalse(AwsSdkMetrics.isDefaultMetricsEnabled());
   // effectively no effect
   AwsSdkMetrics.disableMetrics();
   assertFalse(AwsSdkMetrics.isDefaultMetricsEnabled());
 }
 @Override
 public void disableMetrics() {
   AwsSdkMetrics.disableMetrics();
 }