I would like to create a Map Bubble which will receive live data from a csv or json or any kind of external file. I understand that the way to do that is to use the data module and set data.enablePolling to true.

My static chart is the following:

```
        Highcharts.mapChart('container', {
        chart: {
            borderWidth: 0,
            map: 'custom/world'
        },

        title: {
            text: 'Map'
        },

        subtitle: {
            text: 'Activity in the last 60 minutes'
        },

        legend: {
            enabled: false
        },

        mapNavigation: {
            enabled: false,
            buttonOptions: {
                verticalAlign: 'bottom'
            }
        },

        series: [{
            name: 'Countries',
            color: '#717171',
            enableMouseTracking: true
        }, {
            type: 'mapbubble',
            name: 'Visitors',
            color: '#ff4013',
            joinBy: ['iso-a2', 'code2'],
            data: [{ "code2": "CA", "desc": "Canada", "z": 2 }],
            minSize: 20,
            maxSize: '20%',
            tooltip: {
                pointFormat: '{point.desc}: {point.z} visitors'
            }
        }],

    });

```

Is it possible to import the data by setting data.csvURL, data.rowsURL or data.columnsURL instead of using the series.data ? I have tried but it doesn't seem to work.