public final Subclass withMetricsCollector(RequestMetricCollector metrics) {
        setMetricsCollector(metrics);
        return getSubclass();
    }
Sets a custom RequestMetricCollector to use for the client.

@param metrics Custom RequestMetricCollector to use.
@return This object for method chaining.
aws-java-sdk-core/src/main/java/com/amazonaws/client/builder/AwsClientBuilder.java