So, if Streams are supposed to be a ES-level thing, then using the non-existent JS IDL may be ok (though the TC39 crowd will likely raise some eyebrows). However, I think it should be dumped in preference for a reference implementation of some sort, as is commonly the case for ES features (at least, that's what I've seen in their Wiki). If this is supposed to be a browser API, then I don't think w