clientv3/compare.go
func LeaseValue(key string) Cmp {
	return Cmp{Key: []byte(key), Target: pb.Compare_LEASE}
}
func LeaseValue(key string) Cmp {
	return Cmp{Key: []byte(key), Target: pb.Compare_LEASE}
}
// LeaseValue compares a key's LeaseID to a value of your choosing. The empty
// LeaseID is 0, otherwise known as `NoLease`.