fix(streaming): use iter vec for [DONE] marker

src/server/mod.rs

@@ -242,7 +242,6 @@ async fn chat_completions(
                 );
 
                 // Create SSE stream from aggregating stream
-                // Emit [DONE] immediately when we see finish_reason: "stop"
                 let stream_id = format!("chatcmpl-{}", Uuid::new_v4());
                 let stream_created = chrono::Utc::now().timestamp() as u64;
                 
@@ -250,9 +249,6 @@ async fn chat_completions(
                     .map(move |chunk_result| {
                         match chunk_result {
                             Ok(chunk) => {
-                                // Check if this is the final chunk
-                                let is_final = chunk.finish_reason.as_deref() == Some("stop");
-                                
                                 // Convert provider chunk to OpenAI-compatible SSE event
                                 let response = ChatCompletionStreamResponse {
                                     id: stream_id.clone(),
@@ -272,16 +268,7 @@ async fn chat_completions(
                                 };
 
                                 match Event::default().json_data(response) {
-                                    Ok(event) => {
-                                        // If this is the final chunk, also create [DONE] event
-                                        // We'll return both in a nested stream
-                                        if is_final {
-                                            // Return the final chunk first
-                                            Ok(event)
-                                        } else {
-                                            Ok(event)
-                                        }
-                                    }
+                                    Ok(event) => Ok(event),
                                     Err(e) => {
                                         warn!("Failed to serialize SSE event: {}", e);
                                         Err(AppError::InternalError("SSE serialization failed".to_string()))
@@ -295,9 +282,9 @@ async fn chat_completions(
                         }
                     });
 
-                // Add [DONE] as a separate stream after sse_stream
-                let done_event = Event::default().data("[DONE]");
-                let done_stream = futures::stream::once(async move { Ok(done_event) });
+                // Append [DONE] using iter (not once) - should ensure it gets polled
+                let done_vec = vec![Ok::<Event, AppError>(Event::default().data("[DONE]"))];
+                let done_stream = futures::stream::iter(done_vec);
                 let out = sse_stream.chain(done_stream);
 
                 Ok(Sse::new(out).into_response())