See: Description
| Class | Description | 
|---|---|
| MetricsAccumulator | 
 For resilience,  
Accumulators are required to be wrapped in a Singleton. | 
| MetricsAccumulator.AccumulatorCheckpointingSparkListener | 
 Spark Listener which checkpoints  
MetricsContainerStepMap values for fault-tolerance. | 
| MetricsContainerStepMapAccumulator | 
AccumulatorV2 implementation for MetricsContainerStepMap. | 
| SparkBeamMetricSource | 
 A Spark  
Source that is tailored to expose a SparkBeamMetric, wrapping an
 underlying MetricResults instance. | 
| WithMetricsSupport | 
 A  
MetricRegistry decorator-like that supports AggregatorMetric and SparkBeamMetric as Gauges. |