feat: implement request duration tracking in process_event_with_backoff

Co-Authored-By: Jayant Krishnamurthy <[email protected]>

Author: devin-ai-integration[bot]

apps/fortuna/src/keeper.rs

@@ -374,6 +374,8 @@ pub async fn process_event_with_backoff(
     gas_limit: U256,
     metrics: Arc<KeeperMetrics>,
 ) {
+    let start_time = std::time::Instant::now();
+
     metrics
         .requests
         .get_or_create(&AccountLabel {
@@ -404,6 +406,16 @@ pub async fn process_event_with_backoff(
             tracing::error!("Failed to process event: {:?}", e);
         }
     }
+
+    let duration_ms = start_time.elapsed().as_millis() as f64;
+    metrics
+        .request_duration_ms
+        .get_or_create(&AccountLabel {
+            chain_id: chain_state.id.clone(),
+            address: chain_state.provider_address.to_string(),
+        })
+        .observe(duration_ms);
+
     metrics
         .requests_processed
         .get_or_create(&AccountLabel {