docs: function SecondaryIndexQuery(options, callback) {
      CommandBase.call(this, 'RpbIndexReq', 'RpbIndexResp', callback);
      this.validateOptions(options, schema);
  
      if (this.options.indexKey === null && (this.options.rangeStart === null || this.options.rangeEnd === null)) {
          throw new Error("either 'indexKey' or 'rangeStart' + 'rangeEnd' are required");
      }
  
      if (!this.options.stream) {
          this.responses = [];
      }
  }