Currently, each request is fulfilled as soon as a reply is received. For requests within a multi-block, each request is thus fulfilled with a value of "QUEUED".
Would be nice if we would instead switch to a dedicated state where each "QUEUED" reply only issues a "progress". Each request should be fulfilled once the EXEC-reply has been received which includes an array of all results.
Obviously, we have to cope with invalid requests (nested MULTI), invalid arguments, etc.