@Override
  public boolean isClearRegion() {
    return _operation == EnumListenerEvent.AFTER_REGION_CLEAR;
  }
Returns the unqiue event eventifier for event corresponding to this message.

@return the unqiue event eventifier for event corresponding to this message.
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/ClientUpdateMessageImpl.java