Decoding content-disposition-filename HTTP header

[Nick Shaforostoff]

Hi. Trying to download file with cyrillic filename I get
=?UTF-8?B?0JrRgNC40YLQtdGA0LjQuCDQvtGG0LXQvdC40LLQsNC90LjRjyDQvtGA0LvQvtCy0L7QuS5yYXI=?=
It's obvious that =?UTF-8 part tells us we should decode it as being UTF-8.
I also seen this kind of encoding in email headers

I'n sure that the code to handle this is already written. Can anybody
point me to it?

Ps. Is it correct that the decoding should be made in
TransferJob::slotMetaData()?