C# の UTF8Encoding.UTF8.GetBytes(key) に対応する PHP のメソッドはどれですか? 書き方は？

$s = '中文abc';$s = iconv('gbk', 'utf-8', $s); //不是 utf-8 时需转 utf-8print_r(unpack('C*', $s));

Array(    [1] => 228    [2] => 184    [3] => 173    [4] => 230    [5] => 150    [6] => 135    [7] => 97    [8] => 98    [9] => 99)

            foreach (var c in UTF8Encoding.UTF8.GetBytes("中文abc"))            {                Console.WriteLine(c);            }

$s = '中文abc';$s = iconv('gbk', 'utf-8', $s); //不是 utf-8 时需转 utf-8print_r(unpack('C*', $s));

Array(    [1] => 228    [2] => 184    [3] => 173    [4] => 230    [5] => 150    [6] => 135    [7] => 97    [8] => 98    [9] => 99)

            foreach (var c in UTF8Encoding.UTF8.GetBytes("中文abc"))            {                Console.WriteLine(c);            }