Function rxrs::create_boxed

pub fn create_boxed<'a: 'b, 'b, V: 'a, F, R, SSS: ?Sized>(
    sub: F
) -> LocalBoxedObservable<'a, V, F, R, SSS> where
    F: FnMut(Mss<No, Box<Observer<V> + 'a>>) -> R,
    R: IntoSubRef<SSS> + 'static,