ListItem fromString and offscreen=True

I have been revisiting an old addon I was working on and had some issues with ListItems being slow to create on slow machines like Pi2 etc
The problem was as soon as I called any of the setProp or setInfo function on the ListItems it was very slow, about 10 times slower than not setting any info.
My theory on this is variable marshaling between the Python and C++ interface but I am not sure.

Anyway I was then looking though the latest Kodi 17 python doscs and noticed this
https://codedocs.xyz/AlwinEsch/kodi/grou…3e6a097bd6

does this mean I can create a ListItem object from a string? If so how? Is there any docs on using this? As you can see from the above there are no examples and I can not find anything that shows how to use this.