Function set_activation_handler 

pub fn set_activation_handler(
    scheme: &str,
    handler: impl Fn(&str) + Send + Sync + 'static,
)

Call handler with the activation URI of every notification the user clicks whose URI has scheme (tilo-clocks), on whatever thread the platform reports it, starting with any such click that arrived before (the one that launched the app). Replaces an earlier handler for scheme.