Provides a synchronisation primitive simmilar to a Semaphore in SyncStack.
The SyncStack is a useful when implementing other synchronisation primitives in place of a wait loop; allowing threads to wait for some resource to become available by calling SyncStack::park and be notified when another thread calls SyncStack::pop later.
Author --- daniel.bechaz@gmail.com
Last Moddified --- 2019-06-14