Today we are a little inconsistent in the spec. We imply that the client must specify return-async in order for the service to return async, but in other cases we imply the service may return async if the client specifies either return-async OR wait.

I had a quick chat with James Snell, and he agreed that we should only return async if the client specifically specifies return-async. If the client specifies wait, and not return-async, we should not return asynchronously.

Our options are to:
1) Ignore the wait
2) use wait as a suggestion for how long to wait before timing out the synchronous request
3) leave it undefined (but still say that the service can't use it to return asynchronously if return-async is not specified).

I kinda like 2), using wait without return-async as a hint from the client how long they want to wait before timing out the request.