* Callback pattern that is easier to grok: each message has an optional nested return channel, instead of 2 nested streams
* Return channel is in the Message structure: less arguments and return values to pass around
* Caller can request a pipe as return channel, or pass its own. This makes proxying and advanced plumbing operations much easier.
Signed-off-by: Solomon Hykes <solomon@docker.com>
Solomon Hykes