Consistently use state->arena for http handling

test_benchmark_config.toml

@@ -10,9 +10,8 @@ interfaces = [
 max_request_size_bytes = 1048576  # 1MB
 # Number of I/O threads for handling connections and network events
 io_threads = 8
-epoll_instances = 8
 # Event batch size for epoll processing
-event_batch_size = 64
+event_batch_size = 128
 
 [commit]
 # Minimum length for request_id to ensure sufficient entropy