public boolean isLocked() {
        return lockOwner != null;
    }
@Test
    public void testIsLocked() throws Exception {
        LockGuard stateLock = LockGuard.NOT_LOCKED;
        assertFalse(stateLock.isLocked());

        Address endpoint = newAddress();
        stateLock = new LockGuard(endpoint, TXN, 1000);
        assertTrue(stateLock.isLocked());
    }