Method dispatch

src/state/mod.rs:17–26

(&mut self, action: A)

    }

    pub fn dispatch<A>(&mut self, action: A)
    where
        A: FnOnce(&mut T),
    {
        let mut state = self.state.lock().unwrap();
        action(&mut state);
        for subscriber in &self.subscribers {
            subscriber(&state);
        }
    }

    pub fn subscribe<F>(&mut self, callback: F)
    where