Callbacks are now handled by url and operation type.

It would have been nicer to use the request, but it's unhashable.

Cl-541

plugins/UM3NetworkPrinting/LegacyUM3OutputDevice.py

@@ -1,8 +1,9 @@
 from cura.PrinterOutput.NetworkedPrinterOutputDevice import NetworkedPrinterOutputDevice
 
+
 class LegacyUM3OutputDevice(NetworkedPrinterOutputDevice):
     def __init__(self, device_id, address: str, properties, parent = None):
         super().__init__(device_id = device_id, address = address, properties = properties, parent = parent)
 
     def _update(self):
-        pass
+        super()._update()