Thread Synchronisation: wait for all threads to be in an operating state before continuing initialisation
Enable the initialisation process to synchronise with all active threads ensuring they are operational before continuing init. This ensures all modules (active threads) are fully operational before main thread completes init, which improves both error and success reporting.
Upon synchronisation main thread shall report this event via a notice and via systemd - sd_notify. This support shall be added as part of this ticket. sd_notify shall only be used for systems that run under systemd and are configured for notification. i.e. Windows OS shall not receive sd_notify.