* [Feature] Dump predictions to pickle file for offline evaluation.

* print_log

* [Refactor] Refactor Evaluator to Metric.

* update

* fix lint

* fix doc

* fix lint

* resolve comments

* resolve comments

* remove collect_device from evaluator

* rename

* update evaluator prefix

* update docstring and comments

* update doc

* [Feature]: Add evaluator base class.

* solve comments

* update

* fix