public static void commitTask(org.apache.hadoop.mapreduce.OutputCommitter committer,
Commits a task output. Before committing the task output, we need to know whether some other
task attempt might be racing to commit the same output partition. Therefore, coordinate with
the driver in order to determine whether this attempt can commit (please see SPARK-4879 for
Output commit coordinator is only used when spark.hadoop.outputCommitCoordination.enabled
is set to true (which is the default).