@Override
protected void describe() {
ExOperatorFactory f = new ExOperatorFactory();
CoreOperatorFactory core = new CoreOperatorFactory();
Random rand = f.random(in);
Cogroup cog1 = f.cogroup(rand.out, core.empty(Ex2.class));
Cogroup cog2 = f.cogroup(rand.out, core.empty(Ex2.class));
out.add(cog1.r1);
out.add(cog2.r1);
core.stop(cog1.r2);