public String getFQDNHostname() {
        return hostNameSupplier.getFqdnHostName();
    }
@Test
    void testGetFQDNHostname() {
        try {
            TaskManagerLocation info1 =
                    new TaskManagerLocation(
                            ResourceID.generate(), InetAddress.getByName("127.0.0.1"), 19871);
            assertThat(info1.getFQDNHostname()).isNotNull();

            TaskManagerLocation info2 =
                    new TaskManagerLocation(
                            ResourceID.generate(), InetAddress.getByName("1.2.3.4"), 8888);
            assertThat(info2.getFQDNHostname()).isNotNull();
        } catch (Exception e) {
            e.printStackTrace();
            fail(e.getMessage());
        }
    }