Hand the main thread to the window and continue work in the provided
        function. A state is passed as the first argument that contains a
        `running` flag. The function is expected to exit if the flag becomes
        false. The flag can also be set to false to stop the window event loop
        and continue in the main thread after the `start()` call.

def start(self, work):
        """
        Hand the main thread to the window and continue work in the provided
        function. A state is passed as the first argument that contains a
        `running` flag. The function is expected to exit if the flag becomes
        false. The flag can also be set to false to stop the window event loop
        and continue in the main thread after the `start()` call.
        """
        assert threading.current_thread() == threading.main_thread()
        assert not self.state.running
        self.state.running = True
        self.thread = threading.Thread(target=work, args=(self.state,))
        self.thread.start()
        while self.state.running:
            try:
                before = time.time()
                self.update()
                duration = time.time() - before
                plt.pause(max(0.001, self.refresh - duration))
            except KeyboardInterrupt:
                self.state.running = False
                self.thread.join()
                return