Custom speed for flkty.select(0)?

**Test case:** https://codepen.io/desandro/pen/azqbop

Hi I'm trying to use flkty.select(0) and flkty.next(true) to allow users to go back to the first slide when on the last slide. But I find the transition speed to be too fast, is there a way to customise this speed?

Start with the reduced test case at https://codepen.io/desandro/pen/azqbop and review how flkty.select(0) and flkty.next(true) handle the transition. Determine whether the transition speed can be customized for these calls, and document or implement the behavior so the requested return-to-first-slide speed is controllable.

Written by the indexing model from the issue text.