code: func (r *ReindexDestination) Source() (interface{}, error) {
  	source := make(map[string]interface{})
  	if r.index != "" {
  		source["index"] = r.index
  	}
  	if r.typ != "" {
  		source["type"] = r.typ
  	}
  	if r.routing != "" {
  		source["routing"] = r.routing
  	}
  	if r.opType != "" {
  		source["op_type"] = r.opType
  	}
  	if r.parent != "" {
  		source["parent"] = r.parent
  	}
  	if r.version > 0 {
  		source["version"] = r.version
  	}
  	if r.versionType != "" {
  		source["version_type"] = r.versionType
  	}
  	return source, nil
  }
docs: // Source returns a serializable JSON request for the request.