anchor.diff:  
   * extracts the `after` field from change events and replaces the original event just with this part
   * optionally filters delete and tombstone records, as per the capabilities and requirements of downstream consumers
  -* optionally adds metadata fields from the change event's `source` field, prefixing them with "__" 
  +* optionally adds metadata fields from the change event's `source` field, prefixing them with "__"
   
   The SMT can be applied either to a source connector (Debezium) or a sink connector.
   We generally recommend to apply the transformation on the sink side as it means that the messages stored in Apache Kafka will contain the whole context.
  
positive.code: ----
  
  === Record filtering for delete records
  The SMT provides a special handling for events that signals `delete` operation.
  When a `DELETE` is executed on a datasource then Debezium generates two events:
  
  * a record with `d` operation that contains only old row data
  * (optionally) a record with `null` value and the same key. This record serves as a tombstone marker for Apache Kafka for https://kafka.apache.org/documentation/#compaction[a log compaction process].
  
  Upon processing these two records, the SMT turns the `d` record into another tombstone.
  The user can configure if both records, only one of them or none is filtered out.
  
  [NOTE]
  ====
  The SMT by default filters out *BOTH* delete records as widely used sink connectors such as for JDBC do not support handling of tombstone records at this point.
  ====
  
  === Adding source metadata fields
  The SMT can optionally add metadata fields from the original change event's `source` structure to the final flattened record (prefixed with "__"). This functionality can be used to add things like the table from the change event, or connector specified fields like the Postgres LSN field. For more information on what's available in the source structure see link:../../connectors[the documentation for each connector]
  
  For example, the configuration
  
  
negative.code: ----
  
  to the final flattened record.
  
  For `DELETE` events, this option is only supported when the `delete.handling.mode` option is set to "rewrite".
  
  == Configuration options
  [cols="35%a,10%a,55%a",width=100,options="header,footer",role="table table-bordered table-striped"]
  