@Override
    public CompletionStage<Boolean> deleteAsync(K key) {
        return cache.removeAsync(key);
    }
@Test
    public void testDeleteAsync() throws Exception {
        cache.put(23, "value-23");
        assertTrue(cache.containsKey(23));

        adapter.deleteAsync(23).toCompletableFuture().get();

        assertFalse(cache.containsKey(23));
    }