NGX_HTTP_PRECONDITION_FAILED  735 src/http/modules/ngx_http_dav_module.c             return NGX_HTTP_PRECONDITION_FAILED;
NGX_HTTP_PRECONDITION_FAILED   68 src/http/modules/ngx_http_not_modified_filter_module.c                                                 NGX_HTTP_PRECONDITION_FAILED);
NGX_HTTP_PRECONDITION_FAILED   75 src/http/modules/ngx_http_not_modified_filter_module.c                                                 NGX_HTTP_PRECONDITION_FAILED);