API change in #6363 broke dask gateway

[TomAugspurger]

In #6363, a parameter was removed that makes distributed in compatible with Dask Gateway: dask/dask-gateway#573

I'd recommend we restore that parameter and deprecate it. If it's impossible to restore the previous functionality, we could restore the parameter and perhaps ignore it, just for the signature compatibility (I don't know if dask-gateway was relying on the previous behavior).

[jrbourbeau]

Looking at the linked dask-gateway PR, it looks like removing the fast= keyword from Scheduler.close is the parameter you're referring to @TomAugspurger. cc @fjetter @gjoseph92 who were actively involved on #6363

[mrocklin]

Question, are we doing upstream testing in dask-gateway? If not, does anyone want to take this on? (@TomAugspurger ?)

[jrbourbeau]

From a functional perspective, looking at the Scheduler.close source from an earlier distributed release, it looks like fast= wasn't actually being used

[TomAugspurger]

#6561 has a quick fix up for this.

I'm not sure if dask-gateway is testing against upstream (I didn't see anything at a glance). I might be able to add that this weekend or next.