Don't stop the multi-manager on bad request.

Author: kinyoklion

libs/networking/src/curl_multi_manager.cpp

@@ -112,8 +112,10 @@ int CurlMultiManager::socket_callback(CURL* easy,
         auto [it, inserted] = manager->sockets_.try_emplace(
             s, SocketInfo{s, nullptr, 0});
         if (!manager->start_socket_monitor(&it->second, what)) {
-            // Failed to start monitoring - return error to CURL
-            return -1;
+            // Failed to register socket monitoring. No data received from the
+            // socket will eventually cause a timeout.
+            // We don't want to return -1, because multiple requests can be
+            // using the same multi-manager.
         }
     }