code: protected void invokeCollectorIfPresent() {
  		if (collectorProxy != null) {
  			Serializable data = collectorProxy.collectPartitionData();
  			logger.finer("Got partition data: " + data + ", from collector: " + collectorProxy);
  			sendCollectorDataPartitionReplyMsg(data);
  		} 
  	}
docs: Invoke the user-supplied PartitionCollectorProxy and send the data
  back to the top-level thread.