Children is private

[andrewbaxter]

Thanks for working on this! I was having issues trying to get mkv tags with symphonia and vlc, maybe because the mkv tags are a matrix rather than flat? Not sure.

In the MasterElement struct children is private so library users can't walk the tree. I didn't see any other way to get it other than serialize to json then deserialize.

[andrewbaxter]

Actually, it looks like most of the structures have mostly private members don't implement Deserialize so I think the workaround is to go through untyped json values or else replicate the whole type tree.