Merge pull request #19518 from DxCx/graphql-subscribe

[GraphQL] Update subscribe signature for graphql v0.11.x

types/graphql/index.d.ts

@@ -7,6 +7,7 @@
 //                 Kepennar <https://github.com/kepennar>
 //                 Mikhail Novikov <https://github.com/freiksenet>
 //                 Ivan Goncharov <https://github.com/IvanGoncharov>
+//                 Hagai Cohen <https://github.com/DxCx>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.3
 

types/graphql/subscription/subscribe.d.ts

@@ -14,7 +14,7 @@ export function subscribe(
     operationName?: string,
     fieldResolver?: GraphQLFieldResolver<any, any>,
     subscribeFieldResolver?: GraphQLFieldResolver<any, any>
-): AsyncIterator<ExecutionResult>;
+): Promise<AsyncIterator<ExecutionResult> | ExecutionResult>;
 
 export function createSourceEventStream(
     schema: GraphQLSchema,
@@ -26,4 +26,4 @@ export function createSourceEventStream(
     },
     operationName?: string,
     fieldResolver?: GraphQLFieldResolver<any, any>
-): AsyncIterable<any>;
+): Promise<AsyncIterable<any>>;