pub(crate) fn exchange(qt: &CxxQtThread<Sioul>, shared: &Arc<Shared>)Expand description
An exchange wanted now (a button, a dose answered, a switch, the
minute’s tick), run by the one worker off the window’s thread
(worker); asked while one runs, another follows it. A shared file
saved, seen by the watcher (watcher), wants one too, after a pause.