shutdown

A cold plate holds a few tens of grams of water against seven hundred watts, so temperature rises about two degrees a second and the limit arrives in under twenty. What that timescale rules out, the protection layers that act inside it, and the choice that decides whether you lose a job or the hardware.

The queue is four lines and the shutdown is where it goes wrong. One sentinel per consumer rather than one for all of them, an exception path that cannot silently kill a worker, and a bound that must be small enough to actually apply backpressure.