allow custom function in run_pretrain_routine
🚀 Feature
I would the ability to use custom function before the training start.
Motivation
I am trying to use pytorch-lightning with pytorch quantization.
The goal is to first load the original model.
Then, modify the model after weight has been reloaded.
So, I think there is a need to allow custom function before training.
Alternatives
If I change the model at load, I will not be able to load the weights.
If I modify the model at first forward,
there will be problems if I want to use the module as a normal pytorch module.