You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: stream.rs
    path of file: ./repos/Relm4/relm4/src/component/async
    
    the code of the file until where you have to start completion: use std::fmt::Debug;
use std::pin::Pin;
use std::task::{Context, Pol
    
    fn assert_send<T: Send>(_stream: T) {}

    #[allow(dead_code)]
    struct Test(Rc<()>);

    #[async_trait::async_trait(?Send)]
    impl AsyncComponent for Test {
        type Input = ();
        type Output = ();
        type CommandOutput = ();
        type Init = ();
        type Root = Rc<()>;
        type Widgets = Rc<()>;

        fn init_root() -> Self::Root {
            Rc::default()
        }

        async fn init(
            _init: Self::Init,
            _root: Self::Root,
            _sender: crate::AsyncComponentSender<Self>,
        ) -> AsyncComponentParts<Self> {
            AsyncComponentParts {
                model: Test(Rc::default()),
                widgets: Rc::default(),
            }
        }
    }

    #[gtk::test]
    fn stream_is_send() {
        let stream = Test::builder().launch(()).into_stream();
        assert_send(stream);
    }
}