code: func (a *Action) UnmarshalBinary(blob []byte) error {
  	if len(blob) != 4 {
  		return errors.New("expected length of 4")
  	}
  	*a = Action(binary.LittleEndian.Uint32(blob))
  	return nil
  }
docs: // UnmarshalBinary decodes an Action from bytes.