@RestrictedApi(explanation = "Should only be called in ChoreService", link = "",
      allowedOnPath = ".*/org/apache/hadoop/hbase/ChoreService.java")
  synchronized void setChoreService(ChoreService service) {
    choreService = service;
    timeOfThisRun = -1;
  }
Returns false when the Chore is not currently scheduled with a ChoreService
hbase-common/src/main/java/org/apache/hadoop/hbase/ScheduledChore.java