public <T extends AmazonWebServiceRequest> T withRequestMetricCollector(RequestMetricCollector metricCollector) {
        setRequestMetricCollector(metricCollector);
        @SuppressWarnings("unchecked")
        T t = (T) this;
        return t;
    }
Specifies a request level metric collector which takes precedence over the ones at the http
client level and AWS SDK level.
aws-java-sdk-core/src/main/java/com/amazonaws/AmazonWebServiceRequest.java