Flutter Q

void _showDrawer() {
  ...
}


# Approach 1

Widget left() {
  return new IconButton(
    icon: 'navigation/menu',
    onPressed: _showDrawer
  );
}
return new ToolBar(
  left: left(),
  ...
);


# Approach 2

var left = new IconButton(
  icon: 'navigation/menu',
  onPressed: _showDrawer
);
return new ToolBar(
  left: left,
  ...
);