From 6566ea7d6bdacef9c652aebba9878b53d20b3b18 Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Mon, 11 Jan 2016 17:36:47 +0900
Subject: [PATCH] nghttpx: Update doc

---
 src/shrpx_http2_upstream.cc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/shrpx_http2_upstream.cc b/src/shrpx_http2_upstream.cc
index de1dec18..2c590792 100644
--- a/src/shrpx_http2_upstream.cc
+++ b/src/shrpx_http2_upstream.cc
@@ -554,6 +554,10 @@ int on_frame_send_callback(nghttp2_session *session, const nghttp2_frame *frame,
     auto downstream = make_unique<Downstream>(upstream, handler->get_mcpool(),
                                               promised_stream_id, 0);
 
+    // As long as we use nghttp2_session_mem_send(), setting stream
+    // user data here should not fail.  This is because this callback
+    // is called just after frame was serialized.  So no worries about
+    // hanging Downstream.
     nghttp2_session_set_stream_user_data(session, promised_stream_id,
                                          downstream.get());