While working with AWS ELB integration customers would wish to know the Latency for the application load balancers.

Observation was that we are currently unable to see any data points for the metric on the default dashboards that are provided with the integration and I understand that we are making use of: aws.elb.metrics.Latency.avg field.

From AWS's end we have [TargetResponseTime](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-cloudwatch-metrics.html) which we would like to have in the integration.