Connect to Zero MQ plugin hub (`zmq_plugin.hub.Hub`) using the settings
        from the text entry fields (e.g., hub URI, plugin name).

        Emit `plugin-connected` signal with the new plugin instance after hub
        connection has been established.

def on_connect_button__clicked(self, event):
        '''
        Connect to Zero MQ plugin hub (`zmq_plugin.hub.Hub`) using the settings
        from the text entry fields (e.g., hub URI, plugin name).

        Emit `plugin-connected` signal with the new plugin instance after hub
        connection has been established.
        '''
        hub_uri = self.plugin_uri.get_text()
        ui_plugin_name = self.ui_plugin_name.get_text()

        plugin = self.create_plugin(ui_plugin_name, hub_uri)
        self.init_plugin(plugin)

        self.connect_button.set_sensitive(False)
        self.emit('plugin-connected', plugin)