There are two implementations of the asynchronousEventOccurred() method. One in the ReplayTaskContext, which I removed, and another in the RuntimeTaskContext. The implementation there executes this code

```
		if (this.ephemeralCheckpoint == null) {
			return;
		}

		if (!this.ephemeralCheckpoint.isUndecided()) {
			return;
		}

		// TODO: Remove this and implement decision logic for ephemeral checkpoint
		LOG.error("Checkpoint state of " + this.task.getRuntimeEnvironment().getTaskNameWithIndex() + " is UNDECIDED");
		this.ephemeralCheckpoint.setCheckpointDecisionSynchronously(false);
```

Which seems to do nothing, especially not related to buffer rebalancing.