Log `exitCode` when `SparkContext.stop` starts

23/02/06 02:12:55 INFO SparkContext: SparkContext is stopping with exitCode 0.

Pi is roughly 3.147080
23/02/06 02:12:55 INFO SparkContext: SparkContext is stopping with exitCode 0.
...
23/02/06 02:12:55 INFO AbstractConnector: Stopped Spark@1cb72b8{HTTP/1.1, (http/1.1)}{localhost:4040}
23/02/06 02:12:55 INFO SparkUI: Stopped Spark web UI at http://localhost:4040
23/02/06 02:12:55 INFO MapOutputTrackerMasterEndpoint: MapOutputTrackerMasterEndpoint stopped!
23/02/06 02:12:55 INFO MemoryStore: MemoryStore cleared
23/02/06 02:12:55 INFO BlockManager: BlockManager stopped
23/02/06 02:12:55 INFO BlockManagerMaster: BlockManagerMaster stopped
23/02/06 02:12:55 INFO OutputCommitCoordinator$OutputCommitCoordinatorEndpoint: OutputCommitCoordinator stopped!
23/02/06 02:12:55 INFO SparkContext: Successfully stopped SparkContext
23/02/06 02:12:56 INFO ShutdownHookManager: Shutdown hook called