code: func (r *BulkIndexRequest) UseEasyJSON(enable bool) *BulkIndexRequest {
  	r.useEasyJSON = enable
  	return r
  }
docs: // UseEasyJSON is an experimental setting that enables serialization
  // with github.com/mailru/easyjson, which should in faster serialization
  // time and less allocations, but removed compatibility with encoding/json,
  // usage of unsafe etc. See https://github.com/mailru/easyjson#issues-notes-and-limitations
  // for details. This setting is disabled by default.