code: public void abortCheckpointOnBarrier(long checkpointId, Throwable cause) throws Exception {
  		throw new UnsupportedOperationException(String.format("abortCheckpointOnBarrier not supported by %s", this.getClass().getName()));
  	}
docs: Aborts a checkpoint as the result of receiving possibly some checkpoint barriers,
  but at least one {@link org.apache.flink.runtime.io.network.api.CancelCheckpointMarker}.
  
  <p>This requires implementing tasks to forward a
  {@link org.apache.flink.runtime.io.network.api.CancelCheckpointMarker} to their outputs.
  
  @param checkpointId The ID of the checkpoint to be aborted.
  @param cause The reason why the checkpoint was aborted during alignment