Attachment file with Chinese file name, how to support chinese file name

[function2000]

I try to use send email with attachment, the file name is Chinese, for example 销售报告.pdf,
But when send out, it is as ����.pdf .
Any idea to suppoer Chinese file name?

My code is as below:

for (final path in files) {
        final file = File(path);

        final mediaType = MediaType.guessFromFileExtension(file.path);

        await builder.addFile(file, mediaType);

      }

Thanks a lot!