Function ongoing 

pub fn ongoing(
    title: &str,
    body: &str,
    actions: Vec<(String, String)>,
    on_action: Box<dyn Fn(&str) + Send>,
) -> Ongoing

Shows the notification of something going on. actions are its buttons as (key, label), “default” for a click on it; on_action runs with the key of each one pressed, on the notification’s own thread.