improvement: more efficient /claim

src/api/client_server/keys.rs

@@ -440,13 +440,16 @@ pub(crate) async fn claim_keys_helper(
 
     let mut failures = BTreeMap::new();
 
-    for (server, vec) in get_over_federation {
+    let mut futures: FuturesUnordered<_> = get_over_federation
+        .into_iter()
+        .map(|(server, vec)| async move {
         let mut one_time_keys_input_fed = BTreeMap::new();
             for (user_id, keys) in vec {
                 one_time_keys_input_fed.insert(user_id.clone(), keys.clone());
             }
-        // Ignore failures
+            (
-        if let Ok(keys) = services()
+                server,
+                services()
                     .sending
                     .send_federation_request(
                         server,
@@ -454,13 +457,20 @@ pub(crate) async fn claim_keys_helper(
                             one_time_keys: one_time_keys_input_fed,
                         },
                     )
-            .await
+                    .await,
-        {
+            )
+        }).collect();
+
+    while let Some((server, response)) = futures.next().await {
+        match response {
+            Ok(keys) => {
                 one_time_keys.extend(keys.one_time_keys);
-        } else {
+            }
+            Err(_e) => {
                 failures.insert(server.to_string(), json!({}));
             }
         }
+    }
 
     Ok(claim_keys::v3::Response {
         failures,