Function after_exchange 

fn after_exchange<T>(work: impl FnOnce() -> T) -> T

work begun once the exchange of this Sioul running (told to hurry: its notes and papers wait for the next) is done, and run without holding the window’s exchanges back, a dose’s alarm first: for work that takes the exchanges’ lock itself, a short hold at a time (share::remove_device_files), between which a dose’s exchange goes, or only to put in place what it opened outside it (share::put_back). Under quietly, a dose’s alarm waited for the whole of it.