lease/lessor.go
func (l *Lease) RemainingTTL() int64 {
	if l.remainingTTL > 0 {
		return l.remainingTTL
	}
	return l.ttl
}
func (l *Lease) RemainingTTL() int64 {
	if l.remainingTTL > 0 {
		return l.remainingTTL
	}
	return l.ttl
}
// RemainingTTL returns the last checkpointed remaining TTL of the lease.
// TODO(jpbetz): do not expose this utility method