function is_valid_utf8(string $data): bool {
return mb_check_encoding($data, 'UTF-8');
}
$arr1 = "Hello, 世界";
$arr2 = pack("C*", 0xa3, 0xed, 0xfd);
echo is_valid_utf8($arr1) ? "true\n" : "false\n";
echo is_valid_utf8($arr2) ? "true\n" : "false\n";
/*
run:
true
false
*/