本页
    
    from.createSignedUrls()
    final List<String> signedUrls = await supabase
    .storage
    .from('avatars')
    .createSignedUrls(['folder/avatar1.png', 'folder/avatar2.png'], 60);
  
  Notes
- 需要RLS策略权限。
- buckets表的权限: 没有
- objects表的权限:- select.
 
- 请参考存储指南中关于访问控制的工作方法
Examples
创建签名的URL
    final List<String> signedUrls = await supabase
    .storage
    .from('avatars')
    .createSignedUrls(['folder/avatar1.png', 'folder/avatar2.png'], 60);