pub trait Middleware<Item>: Debug + Send {
    fn create<In>(self, previous: In) -> Pin<Box<dyn Stream<Item = Item>>>
    where
        In: Stream<Item = Item> + 'static,
        Self: Sized + Clone;
}

pub trait MiddlewareExt: Stream {
    fn use_middleware<M>(self, middleware: M) -> Pin<Box<dyn Stream<Item = Self::Item>>>
    where
        M: Middleware<Self::Item> + Clone,
        Self: Sized + 'static,
    {
        middleware.create(self)
    }
}
impl<T: Stream> MiddlewareExt for T {}