Bobby Wang 9d2832a3a3
fix potential TaskFailedListener's callback won't be called (#6612)
there is possibility that onJobStart of TaskFailedListener won't be called, if
the job is submitted before the other thread adds addSparkListener.

detail can be found at https://github.com/dmlc/xgboost/pull/6019#issuecomment-760937628
2021-01-21 14:20:32 +08:00
..