If enabled it will force the VAE to run in float32 for high image resolution pipelines, such as SD-XL. VAE
can be fine-tuned / trained to a lower range without loosing too much precision in which case
`force_upcast` can be set to `False` - see: https://huggingface.co/madebyollin/sdxl-vae-fp16-fix
mid_block_add_attention (`bool`, *optional*, default to `True`):
If enabled, the mid_block of the Encoder and Decoder will have attention blocks. If set to false, the
mid_block will only have resnet blocks