fix lambda streaming hanging after return (#487)

* fix lambda hanging after return

* Create lucky-ravens-teach.md

Author: conico974

.changeset/lucky-ravens-teach.md

@@ -0,0 +1,5 @@
+---
+"open-next": patch
+---
+
+fix lambda streaming hanging after return

packages/open-next/src/types/aws-lambda.ts

@@ -9,7 +9,7 @@ export interface ResponseStream extends Writable {
 type Handler = (
   event: APIGatewayProxyEventV2,
   responseStream: ResponseStream,
-  context?: Context,
+  context: Context,
 ) => Promise<any>;
 
 interface Metadata {

packages/open-next/src/wrappers/aws-lambda-streaming.ts

@@ -23,7 +23,12 @@ function formatWarmerResponse(event: WarmerEvent) {
 
 const handler: WrapperHandler = async (handler, converter) =>
   awslambda.streamifyResponse(
-    async (event: AwsLambdaEvent, responseStream): Promise<AwsLambdaReturn> => {
+    async (
+      event: AwsLambdaEvent,
+      responseStream,
+      context,
+    ): Promise<AwsLambdaReturn> => {
+      context.callbackWaitsForEmptyEventLoop = false;
       if ("type" in event) {
         const result = await formatWarmerResponse(event);
         responseStream.end(Buffer.from(JSON.stringify(result)), "utf-8");