Allow 4 concurrent requests in Space queue

app.py

@@ -652,7 +652,7 @@ def main() -> None:
         logging.info("Skipping model preload (set %s=1 to enable).", PRELOAD_ENV_VAR)
 
     demo = build_demo()
-    demo.queue(max_size=4, default_concurrency_limit=1).launch(
+    demo.queue(max_size=4, default_concurrency_limit=4).launch(
         server_name=args.host,
         server_port=args.port,
         share=args.share,