public interface RoutingIterationListener
extends TrainingListener, Cloneable, Serializable

An extension of the TrainingListener interface for those listeners that pass data off to a StatsStorageRouter instance. The most common use case here is in distributed training scenarios: each worker has a set of listeners, that have to be serialized and transferred across the network, to some storage mechanism.
The StatsStorageRouter implementations themselves may not be serializable, or should be shared between multiple workers, so instead, we use a StatsStorageRouterProvider