code: func EncodeKeys(anyObject ...interface{}) ([]byte, error) {
  	var buf bytes.Buffer
  	en := msgp.NewWriter(&buf)
  	for _, obj := range anyObject {
  		if err := en.WriteIntf(obj); err != nil {
  			return nil, fmt.Errorf("Failed to encode key: %v", err)
  		}
  	}
  	return buf.Bytes(), nil
  }
docs: // EncodeKeys encode keys to a blob, for comparing or sorting