title: Full width button, how to align text
body: <p>Trying to figure out if I can align the text in a full width button, i.e a button that has <code>width: double.infinity</code></p>
  
  <p>for example this:</p>
  
  <pre><code>ButtonTheme(
    minWidth: double.infinity,
    child: FlatButton(
      onPressed: () {},
      child: Text('Sign Out', textAlign: TextAlign.left),
    ),
  )
  </code></pre>
  
  <p>produces a centered text button and the alignment cannot be changed.</p>
  
  <p>I have tried a few things but can't figure it out, unless I try to create a custom button.</p>
  
  <p>I'm trying to get a full width button with text:left so the user can click anywhere in the row, and still get the material tap effect.</p>
  
  <p><a href="https://i.stack.imgur.com/ld2Am.png" rel="noreferrer"><img src="https://i.stack.imgur.com/ld2Am.png" alt="enter image description here"></a></p>