@Retained
  public EntryEventImpl getFirstEvent(PartitionedRegion r) {
    if (removeAllPRDataSize == 0) {
      return null;
    }

    @Retained
    EntryEventImpl ev = EntryEventImpl.create(r, removeAllPRData[0].getOp(),
        removeAllPRData[0].getKey(), null /* value */, callbackArg, false /* originRemote */,
        getSender(), true/* generate Callbacks */, removeAllPRData[0].getEventID());
    return ev;
  }
This method is called upon receipt and make the desired changes to the PartitionedRegion Note:
It is very important that this message does NOT cause any deadlocks as the sender will wait
indefinitely for the acknowledgement
geode-core/src/main/java/org/apache/geode/internal/cache/partitioned/RemoveAllPRMessage.java