public void clear() {
        for (Section s : sections) {
            s.clear();
        }
    }
@Test
    public void testClear() {
        ConcurrentLongLongPairHashMap map = ConcurrentLongLongPairHashMap.newBuilder()
                .expectedItems(2)
                .concurrencyLevel(1)
                .autoShrink(true)
                .mapIdleFactor(0.25f)
                .build();
        assertEquals(map.capacity(), 4);

        assertTrue(map.put(1, 1, 11, 11));
        assertTrue(map.put(2, 2, 22, 22));
        assertTrue(map.put(3, 3, 33, 33));

        assertEquals(map.capacity(), 8);
        map.clear();
        assertEquals(map.capacity(), 4);
    }