@Override
  protected void handleInit(Context context) {
  }
Implementation of a send-to-table operator that applies updates to existing records
in the table. If there is no pre-existing record, based on Table's implementation it might attempt to write a
default record and then applies an update.

@param <K> the type of the record key
@param <V> the type of the record value
@param <U> the type of the update applied to this table
samza-core/src/main/java/org/apache/samza/operators/impl/SendToTableWithUpdateOperatorImpl.java