//! On/off light — a single GPIO switched high (on) or low (off), no dimming or
//! color. The Hue Bridge sees an on/off light with no level control.
//!
//! Wiring: an LED load (via a driver appropriate to its current) on GPIO_SWITCH.
//! Add `.inverted()` if the GPIO sinks current from the load's cathode directly.
//!
//! Reference code, not standalone firmware — see `examples/README.md`.