NGX_HTTP_SUB_BUFFERED  494 http/modules/ngx_http_sub_filter_module.c         r->buffered |= NGX_HTTP_SUB_BUFFERED;
NGX_HTTP_SUB_BUFFERED  497 http/modules/ngx_http_sub_filter_module.c         r->buffered &= ~NGX_HTTP_SUB_BUFFERED;