anchor.diff:        "op": "u",
         "ts_ms": 1465491461815,
         "patch": "{\"$set\":{\"first_name\":\"Anne Marie\"}}",
  +      "filter": "{\"_id\" : {\"$numberLong\" : \"1004\"}}",
         "source": {
           "version": "{debezium-version}",
           "connector": "mongodb",
  
positive.code: 
  * The `op` field value is now `u`, signifying that this document changed because of an update
  * The `patch` field appears and has the stringified JSON representation of the actual MongoDB idempotent change to the document, which in this example involves setting the `first_name` field to a new value
  * The `after` field no longer appears
  * The `source` field structure has the same fields as before, but the values are different since this event is from a different position in the oplog
  * The `ts_ms` shows the timestamp that {prodname} processed this event
  
negative.code:     "payload": {
        "op": "d",
        "ts_ms": 1465495462115,
        "filter": "{\"_id\" : {\"$numberLong\" : \"1004\"}}",
        "source": {
          "version": "{debezium-version}",
          "connector": "mongodb",
  