@Test
    public void testSending() {
        ZContext ctx = new ZContext();
        Socket output = ctx.createSocket(ZMQ.PAIR);
        output.bind("inproc://zframe.test");
        Socket input = ctx.createSocket(ZMQ.PAIR);
        input.connect("inproc://zframe.test");

        // Send five different frames, test ZFRAME_MORE
        for (int i = 0; i < 5; i++) {
            ZFrame f = new ZFrame("Hello".getBytes());
            f.sendAndDestroy(output, ZMQ.SNDMORE);
            assertEquals(0, f.size());
        }

        // Send same frame five times
        ZFrame f = new ZFrame("Hello".getBytes());
        for (int i = 0; i < 5; i++) {
            f.sendAndKeep(output, ZMQ.SNDMORE);
        }
        assertEquals(5, f.size());
        ctx.destroy();
    }