perf(clustering) log `push_config` duration to help debugging config export performance
perf(clustering) log `push_config` duration to help debugging config export performance

Co-authored-by: Datong Sun <88ea7fe5b18d86dd626610096bab9e86520f1a58@konghq.com>
Co-authored-by: Harry <f34cc0759bf93a7897f4224dbf1aa937ff4ab45f@gmail.com>
Kong/kong,Kong/kong,Kong/kong