@Override
    public void unregister(@NonNull SchemeWatcher watcher) {
        Assert.notNull(watcher, "Scheme watcher must not be null");
        watchers.remove(watcher);
    }
@Test
    void shouldThrowExceptionWhenUnregisterNullWatcher() {
        assertThrows(IllegalArgumentException.class, () -> watcherManager.unregister(null));
    }