title: type 'int' is not a subtype of type 'String' error in Dart
body: <p>Neither The print statement nor anything below it run, and the error message points to the issue being the last line above starting with <code>var time</code>. I also verified that <code>earthquakes</code> is a growableList, which means that <code>earthquakes[0]</code> should run without issue, but it doesn't... What am I doing wrong? Let me know if the question needs more clarification and I'll provide it.
  Link to <a href="https://imgur.com/a/EhCqMXI" rel="noreferrer">gif</a> of error
  Link to <a href="https://github.com/ThinkDigitalRepair/Quake/blob/master/quake/lib/ui/quake.dart" rel="noreferrer">code</a> on GitHub</p>
  
  <p>The problematic part of my code is as follows. Error reported on line 43.</p>
  
  <pre><code>import 'package:flutter/material.dart';
  import 'dart:async';
  import 'dart:convert';
  import 'package:http/http.dart' as http;
  import 'package:intl/intl.dart';
  
  class Quake extends StatefulWidget {
    var _data;
  
    Quake(this._data);
  
    @override
    State&lt;StatefulWidget&gt; createState() =&gt; new QuakeState(_data);
  }
  
  class QuakeState extends State&lt;Quake&gt; {
    // https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_day.geojson
  
  
  //      "https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_day.geojson";
    var _data;
  
  
    QuakeState(this._data);
  
    @override
    Widget build(BuildContext context) {
  //    debugPrint(_data['features'].runtimeType.toString());
  
      List earthquakes = _data['features'];
      return new Scaffold(
          appBar: new AppBar(
            title: new Text("Quakes - USGS All Earthquakes"),
            backgroundColor: Colors.red,
            centerTitle: true,
          ),
          body: new ListView.builder(
              itemCount: earthquakes.length,
              itemBuilder: (BuildContext context, int index) {
                print("${earthquakes[index]}");
  
                var earthquake = earthquakes[index];
                var time = earthquake['properties']['time'];
                time *= 1000;
  
                //var dateTime = new DateTime.fromMillisecondsSinceEpoch(int.parse(time));
                //time = new DateFormat.yMMMMd(dateTime).add_jm();
                return new ListTile(
                  title: new Text(time ?? "Empty"),
                );
              }));
    }
  }
  
  Future&lt;Map&gt; getJson(String url) async {
    return await http.get(url).then((response) =&gt; json.decode(response.body));
  }
  </code></pre>