as the attention operator. It is recommended to set to None, and allow xFormers to choose the best operator.    Processor for implementing memory efficient attention using xFormers for the Custom Diffusion method.  FusedAttnProcessor2_0  class diffusers.models.attention_processor.FusedAttnProcessor2_0  < source > ( )    Processor for implementing scaled dot-product attention (enabled by default if you’re using PyTorch 2.0).