The Metrics-Region-Source class maintains metrics for a given region.
The Metrics-Region-Aggregate-Source class allows register/deregister of objects of type Metric-Region-Source. The get-Metrics method on Metrics-Region-Source-Aggregate class, gets metrics from all the Metrics-Region-Source objects registered with it.
The Metrics-Region-Source object is deregistered when the region is closed.
When a Metrics-Region-Source object is deregistered, its directly removed from the set maintained by Metrics-Region-Aggregate-Source object. In such a case, the final metrics of Metrics-Region-Source object are lost. These metrics must be logged one last time before the Metrics-Region-Source object is removed.