code: @Override
  	public Map<String, SerializedValue<OptionalFailure<Object>>> getAccumulatorsSerialized() {
  		return aggregateUserAccumulators()
  			.entrySet()
  			.stream()
  			.collect(Collectors.toMap(
  				Map.Entry::getKey,
  				entry -> serializeAccumulator(entry.getKey(), entry.getValue())));
  	}
docs: Gets a serialized accumulator map.
  @return The accumulator map with serialized accumulator values.