AFW.Util.csvWriter creates CSV streams.
A typical usecase is to export items. If you need column titles other then the item names you had to use "column objects" and do something like this:
label: "my custom col title",
value: function(doc) doc.my_item
This now can be done more simple using a string as col config dividing label and value with a pipe:
"my custom col title|my_item".