Improved perf for ME

Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com>

src/transport/middle_proxy/rotation.rs

@@ -0,0 +1,37 @@
+use std::sync::Arc;
+use std::time::Duration;
+
+use tracing::{info, warn};
+
+use crate::crypto::SecureRandom;
+
+use super::MePool;
+
+/// Periodically refresh ME connections to avoid long-lived degradation.
+pub async fn me_rotation_task(pool: Arc<MePool>, rng: Arc<SecureRandom>, interval: Duration) {
+    let interval = interval.max(Duration::from_secs(600));
+    loop {
+        tokio::time::sleep(interval).await;
+
+        let candidate = {
+            let ws = pool.writers.read().await;
+            ws.get(0).cloned()
+        };
+
+        let Some(w) = candidate else {
+            continue;
+        };
+
+        info!(addr = %w.addr, writer_id = w.id, "Rotating ME connection");
+        match pool.connect_one(w.addr, rng.as_ref()).await {
+            Ok(()) => {
+                // Remove old writer after new one is up.
+                pool.remove_writer_and_reroute(w.id).await;
+            }
+            Err(e) => {
+                warn!(addr = %w.addr, writer_id = w.id, error = %e, "ME rotation connect failed");
+            }
+        }
+    }
+}
+