the expected behavior of QCompleter.UnfilteredPopupCompletion is so slow and could even freeze the user interface

The issue was reported nearly ten years ago here, but was ignored for unknown reason , so I reported it again.

If the data model of QCompleter is so huge, such as containing all English words , then the expected behavior of QCompleter.UnfilteredPopupCompletion is so slow and could even freeze the user interface, so improvement should be done to resolve the problem. Here is an example(https://gist.github.com/redstoneleo/d18c575febd195034fec7bc3389fdb02) with the data model to be English words with the first letter starting with 'a' or 'b' , one could type 'accessible' a bit quickly to realize the slowness of the behavior of QCompleter.UnfilteredPopupCompletion in this case.