pub enum Collected<'a> {
    Box(Box<dyn Render + 'a>),
    Ref(&'a (dyn Render + 'a)),
    None
}

impl<'a> Render for Collected<'a> {
    fn render (&self, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
        match self {
            Self::Box(item) => (*item).render(buf, area),
            Self::Ref(item) => (*item).render(buf, area),
            Self::None => Ok(area),
        }
    }
}

pub struct Collector<'a>(pub Vec<Collected<'a>>);

impl<'a, R: Render + 'a> FnOnce<(R)> for Collector<'a> {
    type Output = ();
    extern "rust-call" fn call_once (self, (device, ): (R,)) -> Self::Output {
        self.add(widget.into_collected());
    }
}

impl<'a> Collector<'a> {
    pub fn collect (collect: impl Fn(&mut Collector<'a>)) -> Self {
        let mut items = Self(vec![]);
        collect(&mut items);
        items
    }
    fn add (mut self, widget: Collected<'a>) -> Self {
        self.0.push(widget);
        self
    }
}

pub trait Collection<'a, T, U> {
    fn add (self, widget: impl Render + 'a) -> Self;
}