title: How to add text inside the hole of the Donut Pie Chart in Flutter
body: <p>I would like to add centered text in the middle of donut hole pie chart in Flutter like the image below :<a href="https://i.stack.imgur.com/NetDw.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NetDw.png" alt="enter image description here"></a></p>
  
  <p>I am using <code>charts_flutter: ^0.6.0</code> and this is my code :</p>
  
  <pre class="lang-dart prettyprint-override"><code>new charts.PieChart(
    _project.getExpensesToChartSeries(),
    animate: _animate,
    animationDuration: Duration(milliseconds: 500),
    selectionModels: [
      new charts.SelectionModelConfig(
        type: charts.SelectionModelType.info,
        changedListener: _onSelectionChanged,
      )
    ],
    defaultRenderer: charts.ArcRendererConfig(
      arcWidth: 25,
    ),
  )
  </code></pre>