public class TestChannel {
    private final SimpleNetworkWrapper channel;
    private Side side;

    @Inject
    public TestChannel(Side side) {
        this.side = side;
        channel = NetworkRegistry.INSTANCE.newSimpleChannel("X|test");
        channel.registerMessage(new MessageHandler(), TestMessage.class, 0, Side.CLIENT);
        channel.registerMessage(new MessageHandler(), TestMessage.class, 1, Side.SERVER);
    }

    @SubscribeEvent
    public void onClientConnectedToServer(PlayerEvent.PlayerLoggedInEvent ev) {
        channel.sendToAll(new TestMessage(0));
    }

    private class MessageHandler implements IMessageHandler<TestMessage, IMessage> {

        @Override
        public IMessage onMessage(TestMessage message, MessageContext ctx) {
            System.out.println("received message " + message.message);

            if (side.isClient()) {
//                return new TestMessage(1);
                channel.sendToServer(new TestMessage(1));
            }
            return null;
        }

    }

    public static class TestMessage implements IMessage {
        private int message;

        public TestMessage() {
            // Default constructor is required
        }

        public TestMessage(int message) {
            this.message = message;
        }

        @Override
        public void fromBytes(ByteBuf buf) {
            message = buf.readInt();
        }

        @Override
        public void toBytes(ByteBuf buf) {
            buf.writeInt(message);
        }

    }

}