use futures::sync::mpsc::channel;

impl<T> Drop for futures::sync::mpsc::Receiver<T> {
    fn drop(&mut self) {
        use backtrace::Backtrace;
        let bt = Backtrace::new();
        println!("--> Dropping Receiver {:?}", bt);
    }
}

fn main() {
    let (tx, rx) = channel(0);
    drop(rx);
    println!("hi");
}