code: func (t *prefixTransformers) TransformToStorage(data []byte, context Context) ([]byte, error) {
  	transformer := t.transformers[0]
  	prefixedData := make([]byte, len(transformer.Prefix), len(data)+len(transformer.Prefix))
  	copy(prefixedData, transformer.Prefix)
  	result, err := transformer.Transformer.TransformToStorage(data, context)
  	if err != nil {
  		return nil, err
  	}
  	prefixedData = append(prefixedData, result...)
  	return prefixedData, nil
  }
docs: // TransformToStorage uses the first transformer and adds its prefix to the data.