code: protected final boolean isRequestMetricsEnabled(AmazonWebServiceRequest req) {
          RequestMetricCollector c = req.getRequestMetricCollector(); // request level collector
          if (c != null && c.isEnabled()) {
              return true;
          }
          return isRMCEnabledAtClientOrSdkLevel();
      }
docs: Returns true if request metric collection is applicable to the given
  request; false otherwise.