code: def on_about_to_process(self, plugin, instance):
          
  
          if instance is not None:
              instance_model = self.data["models"]["instances"]
              index = instance_model.items.index(instance)
              index = instance_model.createIndex(index, 0)
              instance_model.setData(index, True, model.IsProcessing)
  
          plugin_model = self.data["models"]["plugins"]
          index = plugin_model.items.index(plugin)
          index = plugin_model.createIndex(index, 0)
          plugin_model.setData(index, True, model.IsProcessing)
          self.info("%s %s" % (self.tr("Processing"), index.data(model.Label)))
docs: Reflect currently running pair in GUI