title: Setting data- attribute in GWT / Bootstrap
body: <p>I am working with GWT and implementing bootstrap through GWT-Bootstrap library.</p>
  
  <p>I can't seem to find a way to add data- attributes to my elements?</p>
  
  <p>I can do it by writing HTML directly:</p>
  
  <pre><code>HTMLPanel htmlPanel = new HTMLPanel("&lt;button type=\"button\" class=\"btn\" data-custom=\"some-custom-data\"&gt;Hello World&lt;/button&gt;");
  menuControl.add(htmlPanel);
  </code></pre>
  
  <p>But that's just ugly and defeat the purpose of using GWT (might as well write a plain HTML code).</p>
  
  <p>I am looking for ways to do something like:</p>
  
  <pre><code>Button button = new Button();
  button.setText("Hello World");
  button.setStyleName("btn");
  // Fine up to here, but now i want:
  button.setAttr("data-custom", "some-custom-data");
  </code></pre>