src/Leevel/Mail/Mail.php
public function attachChinese(string $file): string
    {
        $ext = pathinfo($file, PATHINFO_EXTENSION);

        if ($ext) {
            $file = substr($file, 0, strrpos($file, '.'.$ext));
        }

        return '=?UTF-8?B?'.base64_encode($file).'?='.($ext ? '.'.$ext : '');
    }
public function attachChinese(string $file): string
    {
        $ext = pathinfo($file, PATHINFO_EXTENSION);

        if ($ext) {
            $file = substr($file, 0, strrpos($file, '.'.$ext));
        }

        return '=?UTF-8?B?'.base64_encode($file).'?='.($ext ? '.'.$ext : '');
    }
格式化中文附件名字.

@param string $file

@return string