func HammerMutex(m *DRWMutex, loops int, cdone chan bool) {
	for range loops {
		m.Lock(id, source)
		m.Unlock(context.Background())
	}
	cdone <- true
}

// Borrowed from mutex_test.go
func TestMutex(t *testing.T) {
	loops := 200
	if testing.Short() {
		loops = 5
	}
	c := make(chan bool)
	m := NewDRWMutex(ds, "test")
	for range 10 {
		go HammerMutex(m, loops, c)
	}
	for range 10 {
		<-c