is the common training driver that supports multiple
NLP tasks (e.g., pre-training, GLUE and SQuAD fine-tuning etc) and multiple
models (e.g., BERT, ALBERT, MobileBERT etc).
## Experiment Configuration
[train.py] is driven by configs defined by the [ExperimentConfig](https://github.com/tensorflow/models/blob/master/official/core/config_definitions.py)