Function build_plugin_udf_descriptor 

pub fn build_plugin_udf_descriptor(
    instance: &dyn ScalarUDFImpl,
    invoke: extern "C" fn(args: RVec<SafeUdfArg>, number_rows: usize) -> RResult<SafeArrowColumn, RString>,
) -> Result<PluginUdfDescriptor, PluginInitializationError>

Builds a PluginUdfDescriptor from a ScalarUDFImpl instance and its extern "C" invoke function pointer.