capacity = pageSize = 1<<e; exp = e; r = pageSize -1;
capacity = 0; pageSize = 1024; exp = 10; r = 1023;
    public FastIntBuffer2(int e) {        if (e < 0) {            throw new IllegalArgumentException();        }        size = 0;        capacity = pageSize = 1<<e;        exp = e;        r = pageSize -1;        bufferArrayList = new ArrayList();    }