func (h *dbHashTree) Hash() error {
	return h.Batch(func(tx *bolt.Tx) error {
		return canonicalize(tx, "")
	})
}
func (h *dbHashTree) Hash() error {
	return h.Batch(func(tx *bolt.Tx) error {
		return canonicalize(tx, "")
	})
}
// Hash updates all of the hashes and node size metadata, it also checks
// for conflicts.