Support for deferred/partial responses

[helfer]

At some point in the future, apolloServer should support sending multiple partial responses (over a websocket connection for example). This issue is to keep that in mind while we build the first version which will not have such a feature.

[stubailo]

The talk about GraphQL future at React Europe tomorrow should help us have somewhat of a spec to follow/collaborate on, I think!

[helfer]

Let's wait and see, haha. Curious to see if there will finally be any movement on subscriptions.

[paralin]

When do you guys plan to revisit this?

[helfer]

Closing this issue since this has moved a bit farther into the future. We already have a PR open that would add a ws transport to support this. Other than that, support needs to be added in the execution engine first, so the best thing we can do on the server is support different execution engines, some of which might return observables from the execute function instead of a promise.