Derive JupyterAsyncApp from JupyterApp (#389)

Author: blink1073

jupyter_core/application.py

@@ -286,9 +286,12 @@ def launch_instance(cls, argv: t.Any = None, **kwargs: t.Any) -> None:
         loop.close()
 
 
-class JupyterAsyncApp(Application):
+class JupyterAsyncApp(JupyterApp):
     """A Jupyter application that runs on an asyncio loop."""
 
+    name = "jupyter_async"  # override in subclasses
+    description = "An Async Jupyter Application"
+
     # Set to True for tornado-based apps.
     _prefer_selector_loop = False