Store's set function can return inputs and outputs

[yanguoyu]

If Store's set function can return inputs and outputs, it can't deduct the tx fee when returned. How about letting the tx fee calculate by developers in business code?

On the other hand, shall we let the set function can be calling with chains? Like store.set().set().set()? If so, we maybe need to provide another function to get the inputs and outputs, ex. store.set().set().set().submit()

Can you help me provide any suggestions?