title: How to custom donut thickness using c3.js?
body: <p>I would like to customize a donut chart from c3.js for example the arc thickness.</p>
  
  <p>Any help or pointers are greatly appreciated.</p>
  
  <p><a href="https://i.stack.imgur.com/19W6w.png" rel="noreferrer"><img src="https://i.stack.imgur.com/19W6w.png" alt="C3.js Donut arc thickness"></a></p>
  
  <pre><code>var chart = c3.generate({
      data: {
          columns: [
              ['Data1', 30],
              ['Data2', 50],
          ],
          type : 'donut'
      },
  });
  </code></pre>
  
  <p>Example: <a href="http://jsfiddle.net/ktjhh5qr/1/" rel="noreferrer">http://jsfiddle.net/ktjhh5qr/1/</a></p>