pub fn sleep_us(ctx: &ServiceContext, us: u64)Expand description
Sleep for us microseconds, at the kernel’s resolution.
The kernel’s sleep ends on a scheduler tick on every port but ARMv7 (the Pi 2), which has a
sub-tick timer for sleeps under a quantum and falls back to the tick when its few slots are taken;
elsewhere anything under a quantum becomes a quantum. This is for a pace written in microseconds,
not a hardware hold - a hold that must not be cut short or
stretched belongs to gs::driver::delay. On a machine whose clock the kernel could not calibrate
it is one quantum, the same floor sleep_ms has there.