Flutter Wrap元件實作自動布局

Flutter Wrap元件實作自動布局，目前一行空間不夠時，自動在下一行布局。

Wrap(
  spacing: 8.0, // gap between adjacent chips
  runSpacing: 4.0, // gap between lines
  children: <Widget>[
    Chip(
      avatar: CircleAvatar(backgroundColor: Colors.blue.shade900, child: const Text('AH')),
      label: const Text('Hamilton'),
    ),
    Chip(
      avatar: CircleAvatar(backgroundColor: Colors.blue.shade900, child: const Text('ML')),
      label: const Text('Lafayette'),
    ),
    Chip(
      avatar: CircleAvatar(backgroundColor: Colors.blue.shade900, child: const Text('HM')),
      label: const Text('Mulligan'),
    ),
    Chip(
      avatar: CircleAvatar(backgroundColor: Colors.blue.shade900, child: const Text('JL')),
      label: const Text('Laurens'),
    ),
  ],
)