private void buildScalarMatrixRsp(Duration duration, ParseResult parseResult, ExprQueryRsp response) {
        MetricRspData responseData = new MetricRspData();
        responseData.setResultType(ResultType.MATRIX);
        response.setData(responseData);
        ScalarResult scalarResult = (ScalarResult) parseResult;
        response.setStatus(ResultStatus.SUCCESS);
        MetricRangeData metricData = new MetricRangeData();
        metricData.setValues(
            PromOpUtils.buildMatrixValues(duration, formatDoubleValue(scalarResult.getValue())));
        responseData.getResult().add(metricData);
    }
OAP adopt time step by start/end,
reserve step/timeout param to keep consistent with API protocol.
oap-server/server-query-plugin/promql-plugin/src/main/java/org/apache/skywalking/oap/query/promql/handler/PromQLApiHandler.java