@Override
    public int hashCode() {
        return Objects.hash(type);
    }
@Test
    void testHashCode() {
        DistributionSpec rr1 = new RoundRobinDistributionSpec();
        DistributionSpec rr2 = new RoundRobinDistributionSpec();
        assertEquals(rr1.hashCode(), rr2.hashCode());
    }