// The PID lister returns pidListSequence[i] on the ith call. If i >= length of pidListSequence
// then return the last element of pidListSequence (the sequence is considered to have) stabilized.
func sequenceToPidLister(pidListSequence [][]int) func(string) ([]int, error) {
	var numCalls int
	return func(cgroupName string) ([]int, error) {
		numCalls++
		if len(pidListSequence) == 0 {
			return []int{}, nil