code: func createDelegatingStrategy(options Options) *delegatingStrategy {
  	v := &delegatingStrategy{
  		options: options,
  	}
  	v.replace = createReplaceStrategy(options, v)
  	v.merge = createMergeStrategy(options, v)
  	v.retainKeys = createRetainKeysStrategy(options, v)
  	return v
  }
docs: // createDelegatingStrategy returns a new delegatingStrategy