// also set in base.
func hasCoverageBit(base, snapshot []byte) bool {
	for i := range snapshot {
		if snapshot[i]&base[i] != 0 {
			return true
		}
	}
	return false
}

func countBits(cov []byte) int {
	n := 0
	for _, c := range cov {
		n += bits.OnesCount8(c)
	}
	return n
}

var (
	coverageEnabled  = len(coverage()) > 0
	coverageSnapshot = make([]byte, len(coverage()))