revert: remove dependency on async_recursion

Cargo.lock

@@ -80,17 +80,6 @@ version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5f093eed78becd229346bf859eec0aa4dd7ddde0757287b2b4107a1f09c80002"
 
-[[package]]
-name = "async-recursion"
-version = "1.0.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5fd55a5ba1179988837d24ab4c7cc8ed6efdeff578ede0416b4225a5fca35bd0"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn 2.0.48",
-]
-
 [[package]]
 name = "async-trait"
 version = "0.1.77"
@@ -385,7 +374,6 @@ checksum = "3d7b894f5411737b7867f4827955924d7c254fc9f4d91a6aad6b097804b1018b"
 name = "conduit"
 version = "0.7.0-alpha"
 dependencies = [
- "async-recursion",
  "async-trait",
  "axum",
  "axum-server",

Cargo.toml

@@ -115,7 +115,6 @@ lazy_static = "1.4.0"
 async-trait = "0.1.68"
 
 sd-notify = { version = "0.4.1", optional = true }
-async-recursion = "1.0.5"
 
 [target.'cfg(unix)'.dependencies]
 nix = { version = "0.26.2", features = ["resource"] }

src/service/rooms/event_handler/mod.rs

@@ -8,7 +8,6 @@ use std::{
     time::{Duration, Instant, SystemTime},
 };
 
-use async_recursion::async_recursion;
 use futures_util::{stream::FuturesUnordered, Future, StreamExt};
 use ruma::{
     api::{
@@ -1044,8 +1043,7 @@ impl Service {
     /// d. TODO: Ask other servers over federation?
     #[allow(clippy::type_complexity)]
     #[tracing::instrument(skip_all)]
-    #[async_recursion]
-    pub(crate) async fn fetch_and_handle_outliers<'a>(
+    pub(crate) fn fetch_and_handle_outliers<'a>(
         &'a self,
         origin: &'a ServerName,
         events: &'a [Arc<EventId>],
@@ -1053,7 +1051,9 @@ impl Service {
         room_id: &'a RoomId,
         room_version_id: &'a RoomVersionId,
         pub_key_map: &'a RwLock<BTreeMap<String, BTreeMap<String, Base64>>>,
-    ) -> Vec<(Arc<PduEvent>, Option<BTreeMap<String, CanonicalJsonValue>>)> {
+    ) -> AsyncRecursiveType<'a, Vec<(Arc<PduEvent>, Option<BTreeMap<String, CanonicalJsonValue>>)>>
+    {
+        Box::pin(async move {
             let back_off = |id| async move {
                 match services()
                     .globals
@@ -1065,7 +1065,9 @@ impl Service {
                     hash_map::Entry::Vacant(e) => {
                         e.insert((Instant::now(), 1));
                     }
-                hash_map::Entry::Occupied(mut e) => *e.get_mut() = (Instant::now(), e.get().1 + 1),
+                    hash_map::Entry::Occupied(mut e) => {
+                        *e.get_mut() = (Instant::now(), e.get().1 + 1)
+                    }
                 }
             };
 
@@ -1222,6 +1224,7 @@ impl Service {
                 }
             }
             pdus
+        })
     }
 
     async fn fetch_unknown_prev_events(