feature request for step_window

[kylegilde]

trafficstars

I think it would make a lot of sense to add a "type" argument to this step with the options of "centered" & "lagging".

Ideally, I would really like to use this step in the lagging sense because I do not want to use rows that come from the "future" in my time-based dataset.

[EmilHvitfeldt]

This is a good idea. We would need to think really carefully about how to handle cases of "future" observations.

I would be a great idea to see how much of {slider} we would be able to use