Update RFC based on consensus from Issue #283

When the client initializes a subscription, distinct from the "Subscription Active" acknowledgement, the server may also send an initial response. Typically, subscriptions depend on a combination of input variables and event data in order to "resolve". If a subscription is capable of returning an immediate response when a client subscribes, it may do so.

rfcs/Subscriptions.md

@@ -61,7 +61,7 @@ We'll try to define the irreducible components of a GraphQL Subscriptions system
 
 The lifetime of a subscription looks like this:
 
-* **Subscribe:** the Client initializes a subscription by sending a query and its variables to the server.  When the Subscription is created, the input query and variables are mapped to a set of events to which the Subscription listens.
+* **Subscribe:** the Client initializes a subscription by sending a query and its variables to the server.  When the Subscription is created, the input query and variables are mapped to a set of events to which the Subscription listens. The server _may_ send an initial response from executing the subscription operation. 
 
 * **Publish:** when any of the events associated with the subscription are triggered, the subscription executes the query, variables, and payload and sends the result to the client.