@futurize() is now called with parentheses and can take a max_instances
int argument. This is used for setTypingState to not have more than one
queued calls per room and True/False state and avoids bombing the server
with old ephemeral events after a network loss and reconnection.
For any name not found in rooms data, rely on new
nio.HttpClient.get_displayname() function to get and cache it,
e.g. for our own name if no room is joined and past events from users
who left the room.
@futurize now returns PyQtFuture objects, wrapper for the
concurrent.futures.Future objects that can be used from QML,
to ensure name retrieval does not block the GUI.