func NewLease(l clientv3.Lease, prefix string) clientv3.Lease {
	return &leasePrefix{l, []byte(prefix)}
}
func NewLease(l clientv3.Lease, prefix string) clientv3.Lease {
	return &leasePrefix{l, []byte(prefix)}
}
// NewLease wraps a Lease interface to filter for only keys with a prefix
// and remove that prefix when fetching attached keys through TimeToLive.