func newUniqueEphemeralKey(s *concurrency.Session, prefix string) (*EphemeralKV, error) {
	return newUniqueEphemeralKV(s, prefix, "")
}
func newUniqueEphemeralKey(s *concurrency.Session, prefix string) (*EphemeralKV, error) {
	return newUniqueEphemeralKV(s, prefix, "")
}
// newUniqueEphemeralKey creates a new unique valueless key associated with a session lease