 the timestep embeddings.   timestep_cond (torch.Tensor, optional, defaults to None) —
Additional conditional embeddings for timestep. If provided, the embeddings will be summed with the
timestep_embedding passed through the self.time_embedding layer to obtain the final timestep
embeddings.   attention_mask (torch.Tensor, optional, defaults to None) —
An attention mask of shape (batch, key_tokens) is applied to encoder_hidden_states. If 1 the m