public abstract static class ModelMetrics.MetricBuilder<T extends ModelMetrics.MetricBuilder<T>>
Class used to compute AUCs, CMs & HRs "on the fly" during other passes
over Big Data. This class is intended to be embedded in other MRTask
objects. The perRow method is called once-per-scored-row, and
the reduce method called once per MRTask.reduce, and the <init> called once per MRTask.map.