After a lot of ups and downs, I finally got Space hierarchy caching to work on NeoChat.
The commit is here.
I told in my yesterday's post about how a silly error on my part was not letting caching work as expected.
Now, I have invkoed cacheSpaceHierarchy() once when SortFilterRoomListModel is initialized.
populateSpaceHierarchy() accepts an additional parameter to decide if the UI needs to be updated. According to current logic, the UI shoudn't be updated when the caching happens as a part of class initialization. It must be updated only when user clicks on a Space icon.