DateTimeAxis Label Completed

The date time label is not showing when the screen was initialized. It show properly after user pinching.

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:syncfusion_flutter_charts/charts.dart';
import 'package:syncfusion_flutter_core/core.dart';

void main() {
  // Register your license here
  SyncfusionLicense.registerLicense(null);
  return runApp(ChartApp());
}

class ChartApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Chart Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  // ignore: prefer_const_constructors_in_immutables
  MyHomePage({Key key}) : super(key: key);

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Syncfusion Flutter chart'),
      ),
      body: SfCartesianChart(
        series: [
          SplineSeries<Datum, DateTime>(
            name: 'Water Level',
            dataSource: [
              Datum(DateTime(2020, 2, 12), 43),
              Datum(DateTime(2020, 2, 13), 42),
              Datum(DateTime(2020, 2, 14), 41),
              Datum(DateTime(2020, 2, 15), 44),
              Datum(DateTime(2020, 2, 16), 44),
              Datum(DateTime(2020, 2, 17), 45),
              Datum(DateTime(2020, 2, 18), 41),
              Datum(DateTime(2020, 2, 19), 43),
              Datum(DateTime(2020, 2, 20), 20),
              Datum(DateTime(2020, 2, 21), 38),
              Datum(DateTime(2020, 2, 22), 36),
              Datum(DateTime(2020, 2, 23), 39),
              Datum(DateTime(2020, 2, 24), 40),
              Datum(DateTime(2020, 2, 25), 40),
            ],
            xValueMapper: (Datum datum, int index) => datum.dateTime,
            yValueMapper: (Datum datum, int index) => datum.value,
            markerSettings: MarkerSettings(
              isVisible: true,
            ),
          ),
        ],
        primaryXAxis: DateTimeAxis(
          zoomPosition: 1,
          zoomFactor: 0.25,
        ),
        primaryYAxis: NumericAxis(
          labelFormat: '{value} mm',
          plotBands: [
            PlotBand(
              start: 20,
              end: 30,
              color: Colors.amber,
              opacity: 0.2,
              text: 'level 1',
              textStyle: ChartTextStyle(
                color: Colors.black,
              ),
            ),
            PlotBand(
              start: 30,
              end: 40,
              color: Colors.orange,
              opacity: 0.2,
              text: 'level 2',
              textStyle: ChartTextStyle(
                color: Colors.black,
              ),
            ),
            PlotBand(
              start: 40,
              color: Colors.red,
              opacity: 0.2,
              text: 'level 3',
              textStyle: ChartTextStyle(
                color: Colors.black,
              ),
            ),
          ],
        ),
        tooltipBehavior: TooltipBehavior(
          enable: true,
        ),
        zoomPanBehavior: ZoomPanBehavior(
          enablePanning: true,
          enablePinching: true,
          zoomMode: ZoomMode.x,
        ),
      ),
    );
  }
}

class Datum {
  DateTime dateTime;
  double value;

  Datum(
    this.dateTime,
    this.value,
  );
}