@Override
 protected void syncVars(Sync sync) {
   filter = (Boolean) C.sync("filter", filter, sync);
   continuation = (Finder) C.sync("continuation", continuation, sync);
   pattern = (TriplePattern) C.sync("pattern", pattern, sync);
 }
 @Override
 protected void syncVars(Sync sync) {
   t = (Triple) C.sync("t", t, sync);
 }
 @Override
 protected void syncVars(Sync sync) {
   preloadIn = (Graph) C.sync("preloadIn", preloadIn, sync);
 }