.Tensor, optional):
A tensor that if specified is added to the residual of the middle unet block.   encoder_attention_mask (torch.Tensor) —
A cross-attention mask of shape (batch, sequence_length) is applied to encoder_hidden_states. If
True the mask is kept, otherwise if False it is discarded. Mask will be converted into a bias,
which adds large negative values to the attention scores corresponding to “discard” tokens.   return_dict (bool, opt