Function remind_dose 

pub fn remind_dose(
    title: &str,
    body: &str,
    button: (String, Box<dyn FnOnce() + Send>),
    again: Again,
) -> Sending

A dose’s reminder (docs/health.md, “Knowing”): what remind shows with its button (“Taken”), on a thread of its own, whose first try fits in FIRST_TRY and says what it became (Sending::outcome); then as Again says. “Taken” runs once, however late it is pressed while the notice lives.