...while reworking the application code, it became clear that
actually there are two further quite distinct variants of usage.
And while these could be implemented with some trickery based on
the Thread-wrapper defined thus far, it seems prudent better to
establish a safely confined explicit setup for these cases:
- a fire-and-forget-thread, which manages its own memory autonomously
- a thread with explicit lifecycle, with detectable not-running state
