@Override
    public boolean remove(long value) {
        assert value != nullValue : "remove() called with null-sentinel value " + nullValue;
        return hsa.remove(value);
    }
@Test
    public void testRemove() {
        long key = random.nextLong();
        assertFalse(set.remove(key));
        set.add(key);
        assertTrue(set.remove(key));
    }