I have textarea in silverstripe form, i would like to remove the default class ie class="textarea" from the generated html,instead print class="form-control"

$message = new TextareaField('Message', 'Message ' );
$message->addExtraClass('form-control');
$message->setAttribute('placeholder', 'Message (required)');
$message->setAttribute('rows', '5');
$message->setAttribute('cols', '25');

<div id="Message" class="field textarea rounded">
<label class="left" for="Form_Form_Message">
<div class="middleColumn">
<textarea id="Form_Form_Message" class="textarea" cols="20" rows="5" name="Message"></textarea>
</div>
</div>