Global concurrency
Reference:
better download manager ( if you set concurrent download to 10 if the album have 8 track or 12 track download manager wont start downloading the next album in the list or when it downloads the 10 tracks, it will then continue with the remaining 2 tracks instead of going to the next album in the download list and download 8 tracks, so a single track could slow down whole process of downloading.
Could cause problems with file overwriting and locking. Too much hussle for me, if someone wants to make this they are welcome to make a pull request