Use case workflow:

Create connector with config:

"pipeline": "[{\"$match\": {\"ns.coll\": {\"$regex\": /^(col1|col2)$/}}}]",
"copy.existing": "true",
... 

After some time update pipeline in connector's config to:

"[{\"$match\": {\"ns.coll\": {\"$regex\": /^(col1|col2|col3)$/}}}]"

Desired result after restart:

• save resume token
• somehow understand that need to copy only documents from 'col3' collection
• copy documents from 'col3'
• start streaming from saved resume token

What do you think about it?