apache/incubator-spark — pull request #597 by tsdeng (2014-02-13 21:04:36+00:00)
Title: add event listener when executors are stopped, for sending back final stats

add onExecutorStopped event handler.
So when master command a shutdown, the executors can send the final message reporting its statuses by replying ExecutorFinalState message(currently only hdfsRead is reported, more can be added later).
And the master will wait for all response to comeback within the timeout window.