const runtime.mutexSpinning

8 uses

	runtime (current package)
		lock_spinbit.go#L61: 	mutexSpinning    = 0x100
		lock_spinbit.go#L197: 				next := (v &^ mutexSpinning) | mutexSleeping | mutexLocked
		lock_spinbit.go#L218: 		if !weSpin && v&mutexSpinning == 0 && atomic.Casuintptr(&l.key, v, v|mutexSpinning) {
		lock_spinbit.go#L219: 			v |= mutexSpinning
		lock_spinbit.go#L253: 			next = next &^ mutexSpinning
		lock_spinbit.go#L358: 		v&mutexSpinning == 0 || // no spinners means we must wake
		lock_spinbit.go#L426: 			if v&mutexSpinning == 0 || mutexPreferLowLatency(l) {