Handler for property change event.  We catch certain state
        transitions in order to trigger media transport
        acquisition/release

def _property_change_event_handler(self, signal, transport, *args):
        """
        Handler for property change event.  We catch certain state
        transitions in order to trigger media transport
        acquisition/release
        """
        current_state = self.source.State
        if (self.state == 'connected' and current_state == 'playing'):
            self._acquire_media_transport(transport, 'r')
        elif (self.state == 'playing' and current_state == 'connected'):
            self._release_media_transport(transport, 'r')
        self.state = current_state