public FileDownloader downloader() { return downloader; }
@Test
    public void requireThatDifferentNumberOfConfigServersWork() throws IOException {
        // Empty connection pool in tests etc.
        ConfigserverConfig.Builder builder = new ConfigserverConfig.Builder()
                .configServerDBDir(temporaryFolder.newFolder("serverdb").getAbsolutePath())
                .configDefinitionsDir(temporaryFolder.newFolder("configdefinitions").getAbsolutePath());
        FileServer fileServer = createFileServer(builder);
        assertEquals(0, fileServer.downloader().connectionPool().getSize());

        // Empty connection pool when only one server, no use in downloading from yourself
        List<ConfigserverConfig.Zookeeperserver.Builder> servers = new ArrayList<>();
        ConfigserverConfig.Zookeeperserver.Builder serverBuilder = new ConfigserverConfig.Zookeeperserver.Builder();
        serverBuilder.hostname(HostName.getLocalhost());
        serverBuilder.port(123456);
        servers.add(serverBuilder);
        builder.zookeeperserver(servers);
        fileServer = createFileServer(builder);
        assertEquals(0, fileServer.downloader().connectionPool().getSize());

        // connection pool of size 1 when 2 servers
        ConfigserverConfig.Zookeeperserver.Builder serverBuilder2 = new ConfigserverConfig.Zookeeperserver.Builder();
        serverBuilder2.hostname("bar");
        serverBuilder2.port(123456);
        servers.add(serverBuilder2);
        builder.zookeeperserver(servers);
        fileServer = createFileServer(builder);
        assertEquals(1, fileServer.downloader().connectionPool().getSize());
    }