🐛 Bug

We should make sure that the following work properly in DDP by moving the state variables to in observer.py and fake_quant.py to buffers:

model.apply(torch.quantization.disable_fake_quant)
model.apply(torch.quantization.disable_observer)

To Reproduce

Steps to reproduce the behavior:

Expected behavior

Environment

Please copy and paste the output from our
environment collection script
(or fill out the checklist below manually).

You can get the script and run it with:

wget https://raw.githubusercontent.com/pytorch/pytorch/master/torch/utils/collect_env.py
# For security purposes, please check the contents of collect_env.py before running it.
python collect_env.py

• PyTorch Version (e.g., 1.0):
• OS (e.g., Linux):
• How you installed PyTorch (conda, pip, source):
• Build command you used (if compiling from source):
• Python version:
• CUDA/cuDNN version:
• GPU models and configuration:
• Any other relevant information:

Additional context

cc @pietern @mrshenli @pritamdamania87 @zhaojuanmao @satgera @rohan-varma @gqchen @aazzolini @xush6528 @osalpekar @jiayisuse @agolynski @jerryzh168 @jianyuh @dzhulgakov @raghuramank100 @jamesr66a