title: Flutter - how do I create a modified version of basic material widget?
body: <p>I'm looking to modify the <code>Stepper</code> widget from flutters material widgets.<br>
  In particular I'd like to have a version that does not include the <code>Continue</code> and <code>Cancel</code> buttons but only uses the <code>onStepTapped</code> callback for navigation.</p>
  
  <p>My initial thought was just to <code>extend</code> the Stepper class, but since it's a stateful widget the building happens in the <code>_StepperState</code> class. I guess I'd have to extend that as well and create a new stateful widget extending Stepper and it's state extending StepperState. The latter is not exposed through the <code>flutter/material.dart</code> though and I can't seem to extend it easily to override the <code>_buildVerticalControls</code> method.</p>
  
  <p>Being new to flutter and dart I'm now wondering what the correct way would be to extend / modify existing (stateful) widgets without <code>c&amp;p</code>-ing the entire class?</p>