It'd be nice to update custom metrics on the progress bar status. This would make tqdm super helpful for something like machine learning training where you want to know how well your model is doing.

e,g. before:

0%|3                                             | 27/6000 [08:24<28:42:16, 17.30s/it]

after:

0%|3                                | 27/6000 [08:24<28:42:16, 17.30s/it, 0.1233 loss]