fix(virtualstream): Fix handling of virtual streams for proper shutdown

ts/classes.virtualstream.ts

@@ -380,7 +380,7 @@ export class VirtualStream<T = Uint8Array> implements plugins.typedRequestInterf
 
   public async writeToWebstream(writableStreamArg: WritableStream<T>) {
     const writer = writableStreamArg.getWriter();
-    while(this.keepAlive) {
+    while(this.keepAlive || this.receiveBackpressuredArray.checkHasItems()) {
       await writer.write(await this.fetchData());
     }
   }