If the `checkSpeculatableTasks()` method for all `Schedulable`s are side-effect free, than this one-liner is definitely a perfect match.  But unfortunately, at least `ClusterTaskSetManager.checkSpeculatableTasks()` is not: it collects all speculatable tasks into a `HashSet`, namely `ClusterTaskSetManager.speculatableTasks`.  So short-circuiting doesn't work here.