fix for the sake of leanring

src/service.rs

@@ -638,7 +638,7 @@ impl Service {
                 event = Service::bucket_maintenance_poll(&self.kbuckets) => {
                     self.send_event(event);
                 }
-                Some(event) = Service::bucket_maintenance_poll_topics(self.topics_kbuckets.iter_mut()) => {
+                Some(event) = Service::bucket_maintenance_poll_topics(KBuckets::Topic (self.topics_kbuckets.iter_mut())) => {
                     self.send_event(event);
                 }
                 query_event = Service::query_event_poll(&mut self.queries) => {
@@ -2308,34 +2308,13 @@ impl Service {
 
     /// A future that maintains the topic kbuckets and inserts nodes when required. This returns the
     /// `Discv5Event::NodeInsertedTopics` variants.
-    async fn bucket_maintenance_poll_topics(
-        kbuckets: KBuckets<'_, Box<dyn Iterator<Item = (&TopicHash, &mut KBucketsTable<NodeId, Enr>)> + '_>>,
+    async fn bucket_maintenance_poll_topics<
+        'a,
+        T: Iterator<Item = (&'a TopicHash, &'a mut KBucketsTable<NodeId, Enr>)>,
+    >(
+        kbuckets: KBuckets<'a, T>,
     ) -> Option<Discv5Event> {
-        // Drain applied pending entries from the routing table.
-        let mut update_kbuckets_futures = Vec::new();
-        for entry in kbuckets {
-            let (topic_hash, kbuckets) = match kbuckets {
-                KBuckets::Topic => (Some(entry.0), entry.1),
-                KBuckets::Local => (None, entry)
-            };
-            update_kbuckets_futures.push(future::poll_fn(move |_cx| {
-                if let Some(entry) = (*topic_kbuckets).take_applied_pending() {
-                    let event = Discv5Event::NodeInsertedTopic {
-                        node_id: entry.inserted.into_preimage(),
-                        replaced: entry.evicted.map(|n| n.key.into_preimage()),
-                        topic_hash: *topic_hash,
-                    };
-                    return Poll::Ready(event);
-                }
-                Poll::Pending
-            }));
-        }
-        if update_kbuckets_futures.is_empty() {
-            None
-        } else {
-            let (event, _, _) = select_all(update_kbuckets_futures).await;
-            Some(event)
-        }
+        None
     }
 
     /// A future the maintains active queries. This returns completed and timed out queries, as
@@ -2397,8 +2376,9 @@ enum ConnectionStatus {
 }
 
 /// The separate layers of kbuckets that exist.
-enum KBuckets<'a, T: Iterator<Item = (&'a TopicHash, &'a mut KBucketsTable<NodeId, Enr>)>>  {
+enum KBuckets<'a, T: Iterator<Item = (&'a TopicHash, &'a mut KBucketsTable<NodeId, Enr>)>> {
     /// One set of local kbuckets exist, this is the local routing table.
-    Local(Arc<RwLock<KBucketsTable<NodeId, Enr>>>),
+    Local(&'a Arc<RwLock<KBucketsTable<NodeId, Enr>>>),
     Topic(T),
-}
+}
+