anchor.diff:  
   |3
   |`filter`
  -|Contains the JSON string representation of the MongoDB selection criteria that was used to identify the document to be deleted.
  +|Contains the JSON string representation of the MongoDB selection criteria that was used to identify the document to be deleted (oplog capture mode only).
   
   |4
   |`source`
  
positive.code: * Names of the collection and database that contain the new document.
  * If the event was part of a snapshot.
  * Timestamp for when the change was made in the database and ordinal of the event within the timestamp.
  * Unique identifier of the MongoDB operation, which depends on the version of MongoDB. It is either the `h` field in the oplog event, or a field named `stxnid`, which represents the `lsid` and `txnNumber` fields from the oplog event.
  
  |8
  |`op`
  
negative.code: * Names of the collection and database that contain the updated document.
  * If the event was part of a snapshot.
  * Timestamp for when the change was made in the database and ordinal of the event within the timestamp.
  * Unique identifiers of the MongoDB session `lsid` and transaction number `txnNumber` in case the change was executed inside a transaction.
  
  |===
  
  