bolthelper.go
func (b Bucket) Delete(k [][]byte) error {
	return b.OpenBucket(k[:len(k)-1], func(b Bucket) error {
		return errorsp.WithStacks(b.Bucket.Delete(k[len(k)-1]))
	})
}
func (b Bucket) Delete(k [][]byte) error {
	return b.OpenBucket(k[:len(k)-1], func(b Bucket) error {
		return errorsp.WithStacks(b.Bucket.Delete(k[len(k)-1]))
	})
}
// Delete removes a key from the bucket. If the key does not exist then
// nothing is done and a nil error is returned. Returns an error if the
// bucket was created from a read-only transaction.