Macro pueue_daemon_lib::ok_or_shutdown

macro_rules! ok_or_shutdown {
    ($task_manager : ident, $result : expr) => { ... };
}

This is a little helper macro, which looks at a critical result and shuts the TaskHandler down, if an error occurred. This is mostly used if the state cannot. be written due to IO errors. Those errors are considered unrecoverable and we should initiate a graceful shutdown immediately.