Metrics for independent val loaders vs for val loaders split from training loader

[ntubiolin]

1. Why can't I have split val loaders with independent val loaders? What if I want to not only watch val accuracies but val loss... https://github.com/ntubiolin/xcos/blob/49d3fcf5ada560106bf9083a51dffc1f3abf4d0c/src/pipeline/base_pipeline.py#L137-L142
2. Metric cannot tell whether the loader is correct. My metric for Validator cannot refuse to eat per-batch output when encounteringTrainer https://github.com/ntubiolin/xcos/blob/49d3fcf5ada560106bf9083a51dffc1f3abf4d0c/src/worker/worker_template.py#L64-L70