Add async_cleanup() method to ServerApp trait

---
Refactor cleanup functions to use async/await

Includes-commit: 3cd52fe
Includes-commit: 58946a8
Replicated-from: #193

.bleep

@@ -1 +1 @@
-0d6c0fbd55a4b0d8b5f2ae892a6602457dc61b7e
+e21e3b7e97830f026794014cf1406dd544cac032

pingora-core/src/apps/mod.rs

@@ -51,7 +51,7 @@ pub trait ServerApp {
     ) -> Option<Stream>;
 
     /// This callback will be called once after the service stops listening to its endpoints.
-    fn cleanup(&self) {}
+    async fn cleanup(&self) {}
 }
 
 /// This trait defines the interface of an HTTP application.
@@ -77,7 +77,7 @@ pub trait HttpServerApp {
         None
     }
 
-    fn http_cleanup(&self) {}
+    async fn http_cleanup(&self) {}
 }
 
 #[cfg_attr(not(doc_async_trait), async_trait)]
@@ -141,7 +141,7 @@ where
         }
     }
 
-    fn cleanup(&self) {
-        self.http_cleanup()
+    async fn cleanup(&self) {
+        self.http_cleanup().await;
     }
 }

pingora-core/src/services/listening.rs

@@ -205,7 +205,7 @@ impl<A: ServerApp + Send + Sync + 'static> ServiceTrait for Service<A> {
 
         futures::future::join_all(handlers).await;
         self.listeners.cleanup();
-        self.app_logic.cleanup();
+        self.app_logic.cleanup().await;
     }
 
     fn name(&self) -> &str {

pingora-proxy/src/lib.rs

@@ -614,7 +614,7 @@ where
         self.process_request(session, ctx).await
     }
 
-    fn http_cleanup(&self) {
+    async fn http_cleanup(&self) {
         // Notify all keepalived requests blocking on read_request() to abort
         self.shutdown.notify_waiters();