Advice on EventStreams vs. Observables Proposal

Currently, the evolving FileSystem API[1] makes use of a placeholder host object called an EventStream[2], first proposed in a post by Tab Atkins. It lacks a formal specification, though.

The question is, where should such a concept be specified? I’ve tried to see what became of TC39’s Observables idea (which shares some naming simiilarity with Object.observe(), unfortunately, but might be the logical next step for ideas like EventStream), but I couldn’t find anything, which leads me to believe it hasn’t quite made the cutting board (and I’m imagining TC39 is pretty busy these days).

There may be advantages to this being a host object, particularly since use cases like the enumerate function in the FileSystem API are already early adopters, even if that’s wishful thinking. I’m willing to write the specification for it, with semantics similar to Tab’s original proposal [2] (which are unlikely to stay exactly the same). But if TC39 is working on something, I’d love a pointer to it, and that’s why I thought I’d check in with those that subscribe to this listserv.

Feedback strongly encouraged! And I’m sorry if I’ve missed a TC39 proposal after all; if such a thing exists, a pointer would be invaluable :)

— A*
[1] http://w3c.github.io/filesystem-api/Overview.html
[2] http://www.xanthir.com/b4PV0