nghttp: stop ContinueTimers on response or reset

If the stream itself is reset, or the server sends a final response
immediately, any Expect/Continue handshake should be cancelled.

src/nghttp.cc

@@ -1708,6 +1708,12 @@ void check_response_header(nghttp2_session *session, Request *req) {
     req->res_nva.clear();
     http2::init_hdidx(req->res_hdidx);
     return;
+  } else {
+    // A final response stops any pending Expect/Continue handshake.
+    std::shared_ptr<ContinueTimer> timer = req->continue_timer.lock();
+    if (timer) {
+      timer->stop();
+    }
   }
 
   if (gzip) {
@@ -2044,6 +2050,12 @@ int on_stream_close_callback(nghttp2_session *session, int32_t stream_id,
     return 0;
   }
 
+  // If this request is using Expect/Continue, stop its ContinueTimer.
+  std::shared_ptr<ContinueTimer> timer = req->continue_timer.lock();
+  if (timer) {
+    timer->stop();
+  }
+
   update_html_parser(client, req, nullptr, 0, 1);
   ++client->complete;