code: func (builder *RequestBuilder) SetDAGRequest(dag *tipb.DAGRequest) *RequestBuilder {
  	if builder.err != nil {
  		return builder
  	}
  
  	builder.Request.Tp = kv.ReqTypeDAG
  	builder.Request.StartTs = dag.StartTs
  	builder.Request.Data, builder.err = dag.Marshal()
  	return builder
  }
docs: // SetDAGRequest sets the request type to "ReqTypeDAG" and construct request data.