FluxTransformer2DModel  
The Transformer model introduced in Flux.  
Reference: https://blackforestlabs.ai/announcing-black-forest-labs/  
Args:
patch_size (`int`, defaults to `1`):
Patch size to turn the input data into small patches.
in_channels (`int`, defaults to `64`):
The number of channels in the input.
out_channels (`int`, *optional*, defaults to `None`):
The number of channels in the output. If not specified, it defaults to `in_channels`.
num_layers (`int`, defaults to `19`):