@Override
    public Set<Entry<Integer, R>> entrySet() {
        assert baseDirInitialized();
        return entrySet;
    }
@Test
    public void eagerLoading() {
        Map.Entry[] b = a.entrySet().toArray(new Map.Entry[3]);
        ((Build) b[0].getValue()).asserts(5);
        ((Build) b[1].getValue()).asserts(3);
        ((Build) b[2].getValue()).asserts(1);
    }