internal static extern void nim_client_get_dnd_config(nim_client_dnd_cb_func cb, IntPtr user_data);
 internal static extern void nim_client_set_dnd_config([MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(NimUtility.Utf8StringMarshaler))] string cfg_json,
                                                       [MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(NimUtility.Utf8StringMarshaler))] string json_extension,
                                                       nim_client_dnd_cb_func cb,
                                                       IntPtr user_data);