@jroper I've rebuilt the action to correspond to the logic you laid out in your last comment, and I think I'm close; as you can see, I cribbed the core concepts from NtetyResultStreamer as you suggested.

Where i'm coming up a bit short is meshing the implementations; in the NettyResultStreamer, we're returning a future so we can take response.body and use that to trigger the bufferingIteratee. 

How can I use the content in the result.body Enumerator to push the takeUpToOneChunk method into working its magic and plucking out the first piece of the response? I understand on a conceptual level what I'm trying to do, but my immaturity with the syntax leaves my implementation frustrated.