code: public void triggerSynchronousSavepoint(long checkpointId, long timestamp, CheckpointOptions checkpointOptions, boolean advanceToEndOfEventTime) {
  		triggerCheckpointHelper(checkpointId, timestamp, checkpointOptions, advanceToEndOfEventTime);
  	}
docs: Trigger a new checkpoint on the task of this execution.
  
  @param checkpointId of th checkpoint to trigger
  @param timestamp of the checkpoint to trigger
  @param checkpointOptions of the checkpoint to trigger
  @param advanceToEndOfEventTime Flag indicating if the source should inject a {@code MAX_WATERMARK} in the pipeline
  to fire any registered event-time timers