datastore/key.go
func (k *Key) String() string {
	if k == nil {
		return ""
	}
	b := bytes.NewBuffer(make([]byte, 0, 512))
	k.marshal(b)
	return b.String()
}
func (k *Key) String() string {
	if k == nil {
		return ""
	}
	b := bytes.NewBuffer(make([]byte, 0, 512))
	k.marshal(b)
	return b.String()
}
// String returns a string representation of the key.