pub fn enumerate_circuits() -> &'static [CircuitAdapter]Expand description
Enumerate every adapter once (cached), deduped to one entry per physical circuit (vendor, device) keeping the preferred backend, and sorted discrete → integrated → other → cpu for a deterministic, index-stable list. Returns an empty slice on a headless / GPU-less box.
The returned indices are the stable handles used by try_device_for_adapter,
primary_circuit_index, and auxiliary_circuit_index.