// For each call, unfreezeServices must be called once.
func freezeServices() {
	// Use atomics for globalServiceFreeze, so we can read without locking.
	// We need a lock since we are need the 2 atomic values to remain in sync.
	globalServiceFreezeMu.Lock()
	// If multiple calls, first one creates channel.
	globalServiceFreezeCnt++
	if globalServiceFreezeCnt == 1 {
		globalServiceFreeze.Store(make(chan struct{}))
	}