bolthelper.go
func (tx Tx) Delete(k [][]byte) error {
	if len(k) == 1 {
		return errorsp.WithStacks(tx.Tx.DeleteBucket(k[0]))
	}
	return tx.Bucket(k[:len(k)-1], func(b Bucket) error {
		return errorsp.WithStacks(b.Bucket.Delete(k[len(k)-1]))
	})
}
func (tx Tx) Delete(k [][]byte) error {
	if len(k) == 1 {
		return errorsp.WithStacks(tx.Tx.DeleteBucket(k[0]))
	}
	return tx.Bucket(k[:len(k)-1], func(b Bucket) error {
		return errorsp.WithStacks(b.Bucket.Delete(k[len(k)-1]))
	})
}
// Delete deletes a key.