Comment by abendstolz

                match Plugin::instantiate_async(&mut store, &component, &linker).await {
                    Ok(plugin) => {
                        match plugin
                            .plugin_guest_oncallback()
                            .call_ontimedcallback(&mut store, &callback_name)
                            .await
                        {
                            Ok(()) => debug!("Successfully called oncallback for {plugin_path:?}"),
                            Err(e) => warn!("Failed to call oncallback for {plugin_path:?}: {e}"),
                        }
                    }
                    Err(e) => {
                        error!("Failed to call oncallback for {plugin_path:?}!: {e}");
                    }
                }

See the "call_ontimedcallback"? It's not a string. The compiler ensures it exists on the Plugin type generated from the .wit file.

If of course I put a wasm file in the plugin folder that doesn't adhere to that definition, that wasm file isn't considered a plugin.