@Test
void getOrComputeSlow() throws InterruptedException {

    final LongCache<String> lc = new LongCache<>(10);
    Thread t1 = new Thread(() -> lc.getOrCompute("t1", () -> {
        pause(1000);
        return 1L;
    }));
    t1.start();
    pause(100);
    lc.getOrCompute("main", () -> 2L);
    t1.join();
}