docs: static Watch forQuery(Query query) {
      Target.Builder target = Target.newBuilder();
      target.setQuery(
          QueryTarget.newBuilder()
              .setStructuredQuery(query.buildQuery())
              .setParent(query.getResourcePath().getParent().getName())
              .build());
      target.setTargetId(WATCH_TARGET_ID);
  
      return new Watch((FirestoreImpl) query.getFirestore(), query, target.build());
    }