text: Title: [FEATURE] FAN support
  Body: **Is your feature request related to a problem? Please describe.**
  Models that are invariant under non-differentiable impairments like JPEG compression, video compression (H265, VP9, etc), etc.
  
  **Describe the solution you'd like**
  [This paper](https://arxiv.org/pdf/2204.12451.pdf) suggests they've solved this with ViT-like models and enhanced attention, called [FAN](https://github.com/nvlabs/fan)
  
  **Describe alternatives you've considered**
  Trained with differentiable approximations of non-differentiable impairments. Works a bit but not great.
  