GitLab

* Initial callback proposal

* Finish various callbacks

* Post-rebase conflicts

* Fix tests

* Don't use something that's not set

* Documentation

* Remove unwanted print.

* Document all models can work

* Add tests + small fixes

* Update docs/source/internal/trainer_utils.rst
Co-authored-by: Lysandre Debut <lysandre@huggingface.co>

* Address review comments

* Fix TF tests

* Real fix this time

* This one should work

* Fix typo

* Really fix typo
Co-authored-by: Lysandre Debut <lysandre@huggingface.co>