Register a Metric with Spark's org.apache.spark.metrics.MetricsSystem.
Register a Metric with Spark's org.apache.spark.metrics.MetricsSystem.
Since updates to an external MetricRegistry that is already registered with the org.apache.spark.metrics.MetricsSystem aren't propagated to Spark's internal MetricRegistry instance, a new MetricRegistry must be created for each new Metric that needs to be published.
name of the Metric
Metric instance to be published