title: Flutter textfield expand as user types
body: <p>I have a textfield and need to have multi-line as below so that the text wraps, however it takes up the space of all the lines that is defined in maxLines.  I want to be able to have it look like 1 line and expand as the text wraps.  Any ideas of how to do this is flutter?</p>
  
  <pre><code>new TextField(
                  decoration: const InputDecoration(
                    hintText: 'Reply',
                    labelText: 'Reply:',
                  ),
                  autofocus: false,
                  focusNode: _focusnode,
                  maxLines: 1,
                  controller: _newreplycontroller,
                  keyboardType: TextInputType.text,
                ),
  </code></pre>