Fix: set connected before send stream data

Co-authored-by: Xin Liao <liaoxinbit@126.com>

src/brpc/policy/baidu_rpc_protocol.cpp

@@ -247,6 +247,14 @@ void SendRpcResponse(int64_t correlation_id,
     // Send rpc response over stream even if server side failed to create
     // stream for some reason.
     if(cntl->has_remote_stream()){
+        // In certain cases, if the server-side stream is actively closing the stream.
+        // The client-side cannot receive on_closed message due to connectted is not set.
+        // We should set connected before send stream data.
+        if (stream_ptr) {
+            // Now it's ok the mark this server-side stream as connectted as all the
+            // written user data would follower the RPC response.
+            ((Stream*)stream_ptr->conn())->SetConnected();
+        }
         // Send the response over stream to notify that this stream connection
         // is successfully built.
         // Response_stream can be INVALID_STREAM_ID when error occurs.
@@ -262,12 +270,6 @@ void SendRpcResponse(int64_t correlation_id,
             }
             return;
         }
-
-        if(stream_ptr) {
-            // Now it's ok the mark this server-side stream as connected as all the
-            // written user data would follower the RPC response.
-            ((Stream*)stream_ptr->conn())->SetConnected();
-        }
     } else{
         // Have the risk of unlimited pending responses, in which case, tell
         // users to set max_concurrency.