stream_filling_sequence function

[wenyihong]

Usage shown in func stream_filling_sequence's comments

filling_stream = stream_filling_sequence(
                model, seq,
                batch_size=1,
                get_masks_and_position_ids=get_func,
                strategy=strategy,
                pre_image=pre_image,
                image=torch_image,
            )
for tokens, logit, mems in filling_stream:
     pass # you can do something or nothing at all
output = strategy.finalize(tokens, mems)[0]