Redraw the figure to show changed data. This is automatically called
        after `start()` was run.

def update(self):
        """
        Redraw the figure to show changed data. This is automatically called
        after `start()` was run.
        """
        assert threading.current_thread() == threading.main_thread()
        for axis, line, interface in self.interfaces:
            line.set_xdata(interface.xdata)
            line.set_ydata(interface.ydata)
            axis.set_xlim(0, interface.width or 1, emit=False)
            axis.set_ylim(0, interface.height or 1, emit=False)
        self.figure.canvas.draw()