Currently we support format and catalog features, which support SPI, but do not support plug-in loading. At the same time, our existing PluginDiscovery and `plugins` are related to the engine, and the new features are not related to the engine. So I expected to add the `spi` directory to support plugins when packaging: "spi/catalog": catalog factory "spi/format": format factory "spi/transform": transform factory
-- Best Regards, Zongwen Li
