Stacked barchart

I might be missing something but I don't think it's possible to create a stacked barchart with the new Charts feature. Looking at Charts.js, it looks like it's a normal barchart but with options:scales:xaxes:stacked (or the equivalent yaxes option) set to true then define a dataset for each segment of the bar. I don't see a place to set the stacked option in BSS

I don't know if this helps or not: