code: func NewNamespacedKV(db *Lowlevel, prefix string) *NamespacedKV {
  	prefixBs := []byte(prefix)
  	// After the conversion from string the cap will be larger than the len (in Go 1.11.5,
  	// 32 bytes cap for small strings). We need to cut it down to ensure append() calls
  	// on the prefix make a new allocation.
  	prefixBs = prefixBs[:len(prefixBs):len(prefixBs)]
  	return &NamespacedKV{
  		db:     db,
  		prefix: prefixBs,
  	}
  }
docs: // NewNamespacedKV returns a new NamespacedKV that lives in the namespace
  // specified by the prefix.