Macro reactive_mutiny::unis_close_async

macro_rules! unis_close_async {
    ($($producer_handle: tt),+) => { ... };
}

Macro to close, atomically, all Unis passed as parameters TODO the closer may receive a time limit to wait – returning how many elements were still there after if gave up waiting TODO busy wait ahead – is it possible to get rid of that without having to poll & sleep? (anyway, this function is not meant to be used in production – unless when quitting the app… so this is not a priority)