public static Collection<HazelcastInstance> getAllHazelcastClients() {
        Set<HazelcastInstance> result = createHashSet(CLIENTS.size());
        for (InstanceFuture<HazelcastClientProxy> f : CLIENTS.values()) {
            result.add(f.get());
        }
        return Collections.unmodifiableCollection(result);
    }
@Test
    public void testGetAllHazelcastClients() {
        HazelcastInstance client1 = HazelcastClient.newHazelcastClient(new ClientConfig()
                .setInstanceName(randomString()));
        HazelcastInstance client2 = HazelcastClient.getOrCreateHazelcastClient(new ClientConfig()
                .setInstanceName(randomString()));

        Collection<HazelcastInstance> clients = HazelcastClient.getAllHazelcastClients();
        assertEquals(2, clients.size());
        assertContains(clients, client1);
        assertContains(clients, client2);
    }