public void setAfterSend(Runnable afterSend) {
    internalAfterSend = afterSend;
  }
Add an internal callback which is run after all data has been sent (for Distributed scope
regions) and any acknowledgements have been received (for Distributed Ack scope regions) a but
before the transaction has been cleaned up.
geode-core/src/main/java/org/apache/geode/internal/cache/TXState.java