Add option to skip subscriptions to children in filter

[AleksandrSl]

We listen for all actions related to children without their subscriptions

[AleksandrSl]

Alas, such an easy solution isn't possible. After we created a syncmap it will try to unsubscribe at the end of its life, but we never subscribed. So we need some flag or copy for a template that only listens for changes and applies them as every sync map does, but subscription to the channel is held outside of it.

[ai]

Let’s avoid the option if it will help. Flexibility become to bloody.

You can track subscribed IDs in Template.subscribed or something like this.